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| publication# 22236 rev: i amendment/0 issue date: september 2005 re f er to amd?s website ( www.amd.com ) f or the latest in f ormation. data sheet am79c875 netphy? 4lp low power quad 10/ 100-tx/fx ethernet transceiver distinctive characteristics four 10/100base-tx ethernet phy transceivers supports rmii (redu ced mii) interface 125 meter (m) mlt-3 and baseline wander operation low power consumption ? 1.3 watt (w) typical (1:1 magnetics) ? 1.2 w typical (1.25:1 magnetics) power management modes: ? selectable 1:1 or 1.25:1 transmit transformer ? unplugged - approximately 100 mw per port ? power down - approximately 3 mw per port single 3.3 v power supply with 5 v i/o tolerance patent-pending dc restoration technique reduces baseline wander susceptibility full and half-duplex operation with full-featured auto-negotiation function next page register support automatic polarity detection during auto- negotiation and 10base-t signal reception unique scramble seed per port reduces emi in switch and repeater applications one port supports 100base-fx function supports inter packet gap as low as 40 ns for high throughput applications no external filters or chokes required compliant with ieee 802.3 standards for 100base-tx, 100base-fx, and 10base-t built-in loopback and test modes small 14 x 20 mm 100-pin pqr package small package allows si de-by-side phy layout ? fits neatly behind quad magnetics ? saves board space over larger 208 pqfp packages support for industrial temperature (-40c to +85c) general description the netphy? 4lp device is a highly integrated, low power 10base-t/100base-tx/fx quad ethernet transceiver. the netphy? 4lp device includes integrated rmii, endecs, scrambler/descrambler, and full-featured auto-negotiation with support for par- allel detection and next page. port 3 can be config- ured as a 100base-fx transm itter to output an nrzi pecl level signal. each receiver has an adaptive equalizer/dc restoration circ uit for accurate clock/data recovery on the 100base-tx signal at different cable lengths and can perform to 125 m and beyond. the netphy? 4lp device operates on a 3.3 v supply and offers 5 v i/o tolerance for mixed signal designs. power consumption is 1.3 w typical for the device, or 0.3 w per port using 1:1 magnetics. the netphy? 4lp device can use 1.25:1 magnetics, which de- creases transmit power co nsumption and reduces de- vice power consumption to 1.2 w typical. the netphy? 4lp device offers an optimized pinout for network applications. rmii pins can be routed di- rectly to the mac and tx/rx media pins are routed di- rectly to the mag netics. direct routing of high speed traces is imperative for project system design and emi noise reduction. the netphy? 4lp device?s on-chip input filtering and output waveshaping eliminates the need of external hy- brid filters for media connection. integrated led logic allows three leds per port to be driven directly. these features greatly simplify th e design of a 100base-x re- peater/switch board, thus requiring minimum external components. for ease of system and chip setup and testing, the net- phy? 4lp device offers loopback and various ad- vanced testing and m onitoring capabilities. the netphy? 4lp device is available in the commer- cial (0c to 70c) or industrial (-40c to +85c) tem- perature ranges. the industrial temperature range is well suited to environment such as enclosures with re- stricted air flow or outdoor equipment.
2 am79c875 block diagram (per port) mac rmii data interface mdc/mdio phyad[4:0] pcs framer carrier detect 4b/5b tp_pmd mlt-3 blw stream cipher 25 mhz 25 mhz 10tx 10rx 20 mhz 100tx 100rx tx+ tx- rx+ rx- transformer interface mux pma clock recovery link monitor signal detect mii serial management interface and registers pll clk generator test led control auto- negotiation 10base-t control/status refclk test [3:0] led drivers rx flp 22236g-1 am79c875 3 connection diagram 22236g-2 4 am79c875 logic symbol am79c875 5 ordering information standard products amd standard products are available in several packages and operat ing ranges. the order number (valid combination) is formed by a combination of the elements below. valid combinations valid combinations list configurations planned to be sup- ported in volume for this device. consult the local amd sales office to confirm availability of specific valid combinations and to check on newly released combinations. device number/description am79c875 netphy? 4lp low power quad 10/100-tx/fx ethernet transceiver temperature range c = commercial (0oc to +70oc) i = industrial (-40oc to +85oc) d = lead-free commercial (0oc to +70oc) f = lead-free industrial (-40oc to +85oc) alternate packaging option package type k = 100-pin plastic quad flat pack (pqr100) am79c875 c/i/d/f k speed option not applicable valid combinations am79c875 kc am79c875 ki am79c875 kd am79c875 kf 6 am79c875 related amd products part no. description integrated controllers am97c973b/975b pcnet-fast? iii single-chip 10/100 mbps pci ethernet contro ller with integrated phy am79c976 pcnet-pro? 10/100 mbps pci ethernet controller am79c978a pcnet-home? single-chip 1/10 mbps pci home networking controller physical layer devices (single-port) am79c874 netphy? 1lp low power 10/100-tx/fx ethernet transceiver am79c901a homephy? single-chip 1/10 mbps home networking phy am79c875 7 table of contents distinctive characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 general description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 block diagram (per port). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 connection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 logic symbol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 standard products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 related amd products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 pin designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 media connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 100base-fx function/test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 rmii signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 led port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 bias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 power and ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 100base-x block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 10base-t block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 auto-negotiation and miscellaneous functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 loopback operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 power savings mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 led port configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 phy control and management block (pcm block) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4 operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 dc characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 power supply current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 switching waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 key to switching waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 9 system clock signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 mlt-3 signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 mii management signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 independent rmii mode signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 physical dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 pqr100 (measured in millimeters) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 errata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 revision b.4 errata summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 errata for netphy? 4lp b.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 revision summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 revision c to d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 revision d to e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 revision e to f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 revision f to g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 revision g to h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 8 am79c875 list of figures figure 1. 100 mbps reception with no errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 figure 2. 100 mbps reception with false carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 figure 3. 100 mbps transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 figure 4. bit ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 figure 5. 10base-t transmit/receive data paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 figure 6. mlt-3 waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 figure 7. tx and rx termination for 100base-tx and 10base-t . . . . . . . . . . . . . . . . . .20 figure 8. led port configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 figure 9. phy management read and write operations . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 figure 10. mlt-3 receive input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 figure 11. mlt-3 and 10base-t test load with 1:1 transformer ratio . . . . . . . . . . . . . . . . . .37 figure 12. mlt-3 and 10base-t test load with 1.25:1 tran sformer ratio . . . . . . . . . . . . . . .37 figure 13. near-end 100base-tx waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 figure 14. near-end 10base-t waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 figure 15. recommended pecl test loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 figure 16. clock signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 figure 17. mlt-3 test waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 figure 18. management bus transmit timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 figure 19. management bus receive timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 figure 20. rmii 100 mbps transmit start of packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 figure 21. rmii 100 mbps transmit end of packet timing . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 figure 22. 100 mbps rmii receive start of packet timing . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 figure 23. 100 mbps rmii receive end of packet timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 figure 24. rmii 10 mbps transmit start of packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 figure 25. rmii 10 mbps transmit end of packet timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 figure 26. 10 mbps rmii receive start of packet timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 figure 27. 10 mbps rmii receive end of packet timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 list of tables table 1. code-group mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 table 2. led display configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 table 3. clause 22 management frame format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 table 4. phy address setting frame structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 table 5. netphy? 4lp mii management register set . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 table 6. legend for register tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 table 7. mii management control register (register 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 table 8. mii management status register (register 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 table 9. phy identifier 1 register (register 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 table 10. phy identifier 2 register (register 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 table 11. auto-negotiation advertisement register (registe r 4) . . . . . . . . . . . . . . . . . . . . . . .28 table 12. auto-negotiation link part ner ability register in base page format (register 5) . .29 table 13. auto-negotiation link part ner ability register in next page format (register 5) . .29 table 14. auto-negotiation expansion register (register 6) . . . . . . . . . . . . . . . . . . . . . . . . . .30 table 15. auto-negotiation next page advertisement regi ster (register 7) . . . . . . . . . . . . . .30 table 16. miscellaneous features register (register 16) . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 table 17. interrupt control/status register (register 17) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 table 18. diagnostic register (register 18) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 table 19. test register (register 19) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 table 20. miscellaneous features 2 register (register 20) . . . . . . . . . . . . . . . . . . . . . . . . . . .32 table 21. receive error counter (register 21) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 table 22. mode control register (register 24) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 am79c875 9 pin designations listed by pin number pin no. pin name pin no. pin name pin no. pin name pin no. pin name 1 rx[0]- 26 tx[3]+ 51 txd[3]_[0] 76 tx_en[1] 2 rx[0]+ 27 agnd 52 ognd 77 cvdd 3 agnd 28 agnd 53 tx_en[3] 78 rxd[0]_[1] 4 agnd 29 rx[3]+ 54 cvdd 79 rxd[0]_[0] 5 tx[0]+ 30 rx[3]- 55 rxd[2]_[1] 80 ovdd 6 tx[0]- 31 avdd 56 rxd [2]_[0] 81 rx_er[0] 7 avdd 32 sdi+/test[0] 57 rx_er[2] 82 crs_dv[0]/ 8 avdd 33 sdi-/test[1] 58 crs_dv[2] 83 cgnd 9 tx[1]- 34 fxr+/test[2] 59 cgnd 84 txd[0]_[1] 10 tx[1]+ 35 fxr-/test[3] 60 txd[2]_[1] 85 txd[0]_[0] 11 agnd 36 fxt+ 61 txd[2]_[0] 86 tx_en[0] 12 agnd 37 fxt- 62 ovdd 87 ognd 13 rx[1]+ 38 leddpx[3]/ scram_en 63 tx_en[2] 88 leddpx[1]/ phyad[4] 14 rx[1]- 39 ledact_link[3]/ anega 64 mdio 89 ledact_link[1]/ phyad[3] 15 avdd 40 ledspd[3]/ burn_in 65 mdc 90 ledspd[1]/ phyad[2] 16 avdd 41 leddpx[2]/dplx 66 r efclk 91 leddpx[0]/fx_dis 17 rx[2]- 42 ledact_link[2] 67 cvdd 92 ledact_link[0] 18 rx[2]+ 43 ledspd[2]/ force100 68 rxd[1]_[1] 93 ledspd[0]/tp1_1 19 agnd 44 ovdd 69 rxd[1]_[0] 94 intr 20 agnd 45 rxd[3]_[1] 70 rx_er[1] 95 rst 21 tx[2]+ 46 rxd[3]_[0] 71 crs_dv[1] 96 gagnd 22 tx[2]- 47 rx_er[3]/ phyad_st 72 ognd 97 ibref 23 avdd 48 crs_dv[3] 73 cgnd 98 gavdd 24 avdd 49 cgnd 74 txd[1]_[1] 99 gavdd 25 tx[3]- 50 txd[3]_[1] 75 txd[1]_[0] 100 avdd 10 am79c875 pin descriptions media connections tx[3:0] transmit output output the tx[3:0] pins are the differential transmit output pairs. the tx[3:0] pins transmit 10base-t or mlt-3 signals depending on the state of the link of the port. rx[3:0] receive input input the rx[3:0] pins are the differential receive input pairs. the rx[3:0] pins can receive 10base-t or mlt-3 signals depending on the state of the link of the port. 100base-fx function/test sdi+/test[0] s i g n a l d e t e c t i n p u t + (for port 3 only) analog input/output this pin indicates signal qua lity status on the fiber-optic link in 100base-fx mode. wh en the signal quality is good, the sdi+ pin should be driven high relative to the sdi- pin. 100base-fx is di sabled when bo th pins are simultaneously pulled low. sdi- can also be used for signal detect common mode voltage input. when in test mode, sdi+, sdi-, fxr+, and fxr- pins are used as test[3:0]. sdi-/test[1] s i g n a l d e t e c t i n p u t - (for port 3 only) analog input/output this pin indicates signal qua lity status on the fiber-optic link in 100base-fx mode. wh en the signal quality is good, the sdi+ pin should be driven high relative to the sdi- pin. 100base-fx is di sabled when bo th pins are simultaneously pulled low. sdi- can also be used for signal detect common mode voltage input. when in test mode, sdi+, sdi-, fxr+, and fxr- pins are used as test[3:0]. fxr+/test[2] f i b e r r e c e i v e i n p u t (for port 3 only) analog input/output when port 3 is configured as fx channel, fxr are ecl level fx receive pins. when in test mode, sdi, and fxr pins are used as test[3:0]. fxr-/test[3] fiber receive input (for port 3 only) analog input/output when port 3 is configured as fx channel, fxr are ecl level fx receive pins. when in test mode, sdi+, sdi-, fxr+, fxr- pins are used as test[3:0]. fxt f i b e r tr a n s m i t o u t p u t (for port 3 only) analog output when port 3 is configured as fx channel, fxt are ecl level fx transmit pins. clock refclk reference clock input signal input the refclk pin is the reference clock input. the refclk signal must be a 50-mhz signal. rmii signals txd[3:0]_[1:0] rmii txd for ports 0 to 3 input these pins are the transmit data input to the rmii of ports 0:3. tx_en[3:0] rmii transmit enable input these pins are the transmit enable inputs to the rmii. rxd[3:0]_[1:0] rmii receive data for ports 0 to 3 output these pins are the receive data for port 0:3. rx_er[2:0] rmii receive error for ports 0 to 2 output these pins indicate receiv e errors for the correspond- ing port. the pin goes high whenever the corresponding receiver detects a symbol error. rx_er[3]/phyad_st rmii receive error fo r port 3 input/output phy address shift this pin indicates receive errors for port 3. it goes high when the corresponding receiver detects a symbol error. at power up, this pin is used to set the phy address by increasing it by 1. if it is high at power up, the phyad of each port is the upper-3 bits and the port number for the lower-2 bits. if it is low, the phyad is incremented by 1. for example, if the pin is high at power-up and the upper-3 bits are set to 000, the phyad of each port (in binary notation) is 00000, 00001, 00010, 00011 re- spectively. if the pin is low at power-up and the upper- 3 bits are set to 000, the phyad of each port is 00001, 00010, 00011, and 00100, respectively. this allows a method of avoiding setting an address to 00000, which could cause problems with some macs. crs_dv[3:0] carrier sense/data valid input/output, pull-down the crs_dv pin is asserted high when media is non-idle. am79c875 11 mdio management data i/o in put/output, pull-down this pin is a bidirectional data interface used by the mac to access management register within the net- phy? 4lp device. this pin has an internal pull-down, therefore, it requires an external pull-up resistor (1.5 k ) as specified in i eee-802.3 section 22. mdc management data clock input, pull-down this pin is the serial management clock which is used to clock mdio data to the mac. rst reset input, pull-up an active low input will force the netphy? 4lp device to a known reset state. reset also can be done through the internal power-on-reset or mii register 0, bit 15. intr interrupt tri-state this pin is true whenever the netphy? 4lp device detects an event flagged as an interrupt. events to be flagged are programmed in register 17. interrupts are cleared on read. the polarity of intr (active high or active low) is set by register 16, bit 14. the default is active low, which requires a 10 k pull-up resistor. led port note: consult the led port configuration section for appropriate pull-up and pull-down resistors. leddpx[0]/fx_dis port [0] duplex led input/output, pull-up low led indicates full-duplex and high indicates half- duplex. fx mode : pulled low at reset will put port 3 in 100base-fx mode. ledact_link[0] port [0] transmit/receive activity led output, pull-up led is output low for approximately 30 ms each time there is activity. link is an active low signal. this signal should have a 1k?4.7k pull-up resistor. ledspd[0]/tp1_1 port [0] speed led input/output, pull-up led is output low when operating in 100base-x modes and high when oper ating in 10base-t modes. tp1_1: pulled low at reset will select transmit trans- former ratio to be 1.25:1. default is 1:1 transformer. leddpx[1]/phyad[4] port [1] duplex led input/output, pull-up led low indicates full-dupl ex and high indicates half- duplex. phy address[4] . this is the first address bit received in the management frame, and one of three msbs for mii management phy address. the two lsbs, phyad [1:0] are internally wired to four ports: phyad [11]=port3,..., phyad [00] = port0. the phyad will also determine the scramble seed, this will help to reduce emi when there are multiple ports switching at the same time. to set this pin, use pull-up or pull-down resistors in the range of 1 k to 4.7 k . ledact_link[1]/phyad[3] port [1] transmit/receive activity led input/output, pull-up led is output low for appr oximately 30 ms each time there is activity. link is an active low signal. phy address[3] . this is the second msb and one of three msb?s for mii management phy address. to set this pin, use pull-up or pull-down resistors in the range of 1 k to 4.7 k . ledspd[1]/phyad[2] port [1] speed led input/output, pull-up led is output low when operating in 100base-x modes and high when operating in 10base-t modes. phy address[2] . this is the third msb and one of three msb?s for mii management phy address. to set this pin, use pull-up or pull-down resistors in the range of 1 k to 4.7 k . leddpx[2]/dplx port [2] duplex led input/output, pull-up led low indicates full-duplex and high indicates half- duplex. dplx: full duplex mode enable . this pin is logically or?ed with a full-duplex enable mii control bit to gener- ate an internal full-duplex enable signal. when as- serted high, the netphy? 4lp device operates in full- duplex mode as determined through auto-negotiation or software setting. when asserted low, the internal control bit (register 0, bit 8) will determine the full-du- plex operating mode. ledact_link[2] port [2] transmit/receive activity led output, pull-up led is output low for appr oximately 30 ms each time there is activity. link is an active low signal. this signal should have a 1k?4.7k pull-up. ledspd[2]/force100 port [2] speed led input/output, pull-up led is output low when operating in 100base-x modes and high when operating in 10base-t modes. force100: force 100base-x operation . when this signal is pulled high and anega is low at reset, all ports will be forced to 100base-tx operation. when asserted low and anega is low, all ports are forced to 12 am79c875 10base-t operation. wh en anega is high, force100 has no effect on operation. leddpx[3]/scram_en port [3] duplex led input/output, pull-up led low indicates full-dupl ex and high indicates half- duplex. scram_en. scra mbler enable. pulled low at reset will bypass the scrambler. default is scrambler enabled. this signal should have a 1k?4.7k pull-up resistor. ledact_link[3]/anega port [3] transmit/receive activity led input/output, pull-up led is low for approximately 30 ms each time there is activity. link is an active low signal. anega: auto-negotiation ability . asserted high means auto-negotiation enab le while low means man- ual selection through dplx, force100. this pin also is reflected as anega bit, mii status register 1, bit 3. ledspd[3]/burn_in port [3] speed led input/output, pull-up led is low when operatin g in 100base-x modes and high when operating in 10base-t modes. burn_in : burn-in mode . burn-in mode for reliability assurance control. this signal should have a 1k?4.7k pull-up resistor. bias ibref reference bias resistor analog to be tied to an external 10-k (1%) resistor which should be connected to th e analog ground at the other end. power and ground ovdd power digital these pins are the digital +3.3 v power supply for i/o. ognd ground digital these pins are the digital ground for i/o. cvdd power digital these pins are the digital +3.3 v power supply for the core logic. cgnd ground digital these pins are the digital ground for core logic. avdd power analog these pins are the +3.3v power supply for analog circuit. agnd ground analog these pins are the ground for analog circuit. gavdd power analog these pins are the +3.3 v power supply for common analog circuits. gagnd ground analog this pin is the ground for common analog circuits. am79c875 13 functional description overview the netphy? 4lp transceiver is a four-port cmos device that implements the complete physical layer for 10base-t and the physical coding sublayer (pcs), physical medium attachment (pma), and physical me- dium dependent (pmd) func tionality for 100base-tx. the netphy? 4lp transceiver implements auto-ne- gotiation allowing two devices connected across a link segment to take maximum advantage of their capabili- ties. auto-negotiation is performed as defined in the ieee 802.3u sp ecification. the netphy? 4lp device communicates with a switch or mac device through the reduced media in- dependent interface (rmii). the netphy? 4lp device co nsists of the following functional blocks: rmii functional blocks 100base-x block including: ? transmit and receive state machines ? 4b/5b encoder and decoder ? stream cipher scrambler and descrambler ? link monitor state machine ? far end fault indication (fefi) state machine ? mlt-3 encoder ? mlt-3 decoder with adaptive equalization 10base-t block including: ? manchester encoder/decoder ? jabber ? receive polarity detect ? waveshaping and filtering carrier integrity monitor auto-negotiation status leds phy control and management modes of operation the rmii interface provides the data path connection between the netphy? 4lp transceivers and the media access controller (mac), repeater, or switch de- vices. the mdc and mdio pins are responsible for communication between the netphy? 4lp trans- ceiver and the station management entity (sta). the rmii standard reduces the pin count by halving the number of data pins, eliminating pins not used in switch applications, and using a single global clock. each port has an independent rmii. rmii uses seven pins per port. they are as follows: receive data rxd[x]_[1:0] carrier sense crs_dv[x] receive error rx_er[x] transmit data txd[x]_[1:0] transmit enable tx_en[x] note: [x] refers to the port. in rmii mode, ref_clk must be sourced by a 50-mhz clock signal. rmii pin descriptions crs_dv carrier sense/receive data valid crs_dv is asserted by the phy when the receive me- dium is non-idle. loss of ca rrier results in the deasser- tion of crs_dv synchronous to the cycle of ref_clk, which presents the first di-bit of a nibble onto rxd[1:0] (i.e., crs_dv is deasserted only on nibble bound- aries). if the phy has additional bits to be presented on rxd[1:0] following the init ial deassertion of crs_dv, the phy asserts crs_dv on cycles of ref_clk which present the second di-bit of each nibble. the phy deasserts crs_dv on cycles of ref_clk which present the first di-bit of the nibble. as a result, starting on the byte boundaries, crs_dv toggles at 25 mhz in 100 mbps mode and 2.5 mhz in 10 mbps mode when crs ends before rx_dv (i.e., the fifo still has bits to transfer when the carrier event ends). therefore, the mac can accurately recove r rx_dv and crs. refer to figure 1. during a false carrier ev ent, crs_dv remains as- serted for the duration of carrier activity. refer to figure 2. the data on rxd[1:0] is considered valid once crs_dv is asserted. howeve r, since the assertion of crs_dv is asynchronous relative to ref_clk, the data on rxd[1:0] is ?00? until proper receive signal decoding takes place. note: crs_dv is asserted asynchronously in order to minimize latency of control signals through the phy. 14 am79c875 note: crs_dv may toggle at 25 mhz starting on a nibble bou ndary if bits accumulate due to the difference be- tween crs and rx_dv. the example waveform shows a single nibble accumulated in the fifo. figure 1. 100 mbps rece ption with no errors figure 2. 100 mbps reception with false carrier rxd[1:0] receive data [1:0] rxd[1:0] transitions sy nchronously to ref_clk. upon assertion of crs_dv, the phy will ensure that rxd[1:0] = 00 until proper receive decoding takes place. then for each clock period in which crs_dv is asserted, rxd[1:0] transfers two bits of recovered data from the phy. rxd[1:0] in 100 mbps mode for normal reception following assertion of crs_dv, rxd[1:0] is ?00? until the receiver has determined that the receive event has a proper start of stream delim- iter (ssd), which is a /j/k/ pair. thereafter, preamble will appear (rxd[1:0] = 01). data capture by macs occur following detection of sfd. if false carrier is detected (an event starting with any- thing other than /j/k/), then rxd[1:0] is?10? until the end of the receive event. this is a unique pattern since false carrier can only occu r at the beginning of a packet where a preamble will be decoded (i.e., rxd[1:0]=01). rxd[1:0] in 10 mbps mode following assertion of crs_dv, rxd[1:0] shall be ?00? until the 10base-t phy has recovered clock and is able to decode the receive data. once valid receive data is available from the 10base-t phy, rxd[1:0] takes on the recovered data values (i.e., starting with ?01? for preamble). at a ref_clk frequency of 50 mhz, the value on rxd[1:0] is valid such that rxd[1:0] may be sampled every tenth cycle, regardless of the starting cycle within the group and yield the correct frame data. 0 0 0 0 0 0 0 0 0 0 0 0 1 a c d e f 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 a b c d e f 0 0 /j/ /k/ preamble sfd data ref_clk crs_dv rxd[1] rxd[0] b 22236g-3 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 ref_clk crs_dv rxd[1] rxd[0] false carrier detected 00000000000000000000 0 22236g-4 am79c875 15 txd[1:0] transmit data txd[1:0] transitions synchronously with respect to ref_clk. when tx_en is asserted, txd[1:0] is ac- cepted for transmission by the phy. txd[1:0] is ignored by the phy while tx_en is deasserted. txd[1:0] in 100 mbps mode txd[1:0] provides valid data for each ref_clk period while tx_en is asserted. refer to figure 3. txd[1:0] in 10 mbps mode as the ref_clk frequency is ten times the data rate in 10 mbps mode, the value on txd[1:0] is valid such that txd[1:0] may be sampl ed every tenth cycle, re- gardless of the starting cycle within the group and yield the correct frame data. bit ordering transmission and reception of each octet is done a di- bit at a time with the orde r of di-bit transmission and reception as shown in figure 4. figure 3. 100 mbps transmission figure 4. bit ordering 100base-x block the functions performed by the device include encod- ing of mii 4-bit data (4b/5b), decoding of received code groups (5b/4b), generating carrier sense and collision detect indications, serializat ion of code groups for transmission, de-serialization of serial data from recep- tion, mapping of transmit, receive, and carrier sense at the rmii interface, and recovery of clock from the in- coming data stream. it offers stream cipher scrambling and descrambling capabilit y for 100base-tx applica- tions. in the transmit data path for 100 mbps, the netphy? 4lp transceiver receives 2-bit wide data across the rmii at 50 million di-bits per second. for 100base-tx applications, it encodes and scrambles the data, serializes it, and transmits an mlt-3 data stream to the media via an isolation trans- former. for 100base-fx app lications, it encodes and serializes the data and transmits a pseudo-ecl (pecl) data stream to the fiber optic transmitter. the netphy? 4lp transceiver receives an mlt-3 data stream from the netw ork for 100base-tx. it then recovers the clock from the data stream, de-serializes the data stream, and descrambles/decodes the data stream (5b/4b) before presenting it at the rmii inter- face. for 100base-fx operation, the netphy? 4lp re- ceives a pecl data stream from the fiber optic trans- ceiver and decodes that data stream. 100base-fx operation is possible only on port 3. 0 0 0 0 0 0 0 0 0 0 0 0 1 a b c d e f 0 0 a b c d e f 0 0 ref_clk tx_en txd[1] txd[0] preamble sfd data 1 1 1 1 1 1 1 1 1 1 1 1 1 22236g-5 d0 d1 d2 d3 d4 d5 d6 d7 first bit first nibble second nibble mac's serial bit stream d0 d1 lsb msb txd[0]/rxd[0] txd[1]/rxd[1] di-bit stream 22236g-6 16 am79c875 within the netphy? 4lp devic e, this block is repli- cated for each port. the rmii signals should be taken in context with the port being referred. the 100base-x block consists of the following sub-blocks: ? transmit process ? receive process ? internal loopback paths ? 4b/5b encoder and decoder ? scrambler/descrambler ? link monitor ? far end fault generation and detection & code-group generator ? mlt-3 encoder/decoder with adaptive equaliza- tion ? serializer/deserializ er and clock recovery ? baseline restoration transmit process the transmit process generates code-groups based on the transmit control and data signals on the rmii. this process is also responsible for frame encapsulation into a physical layer str eam, generating the collision signal based on whether a carrier is received simulta- neously with transmission and generating the carrier sense crs signal at the rmii. the transmit process is implemented in compliance with the transmit state dia- gram as defined in clause 24 of the ieee 802.3u spec- ification. receive process the receive process passes to the rmii a sequence of data derived from the incoming code-groups. each code-group is comprised of five code-bits. this process detects channel activity and then aligns the incoming code bits in code-group boundaries for subsequent data decoding. the receive process is responsible for code-group alignment and al so generates the carrier sense (crs) signal at the rmii. the receive process is implemented in complianc e with the receive state di- agram as defined in clause 24 of the ieee 802.3u specification. the false carr ier indication as specified in the standard is also generated by this block, and communicated to the reconc iliation layer through rxd and rx_er. encoder/decoder the 100 mbps process in the netphy? 4lp device uses the 4b/5b encoding sc heme as defined in ieee 802.3, section 24. this scheme converts between raw data on the rmii and encoded data on the media pins. the encoder converts raw data to the 4b/5b code. it also inserts the stream boundary delimiters (/j/k/ and / t/r/) at the beginning and end of the data stream as appropriate. the decoder converts between encoded data on the media pins and raw data on the rmii. it also detects the stream boundary delimiters to help deter- mine the start and end of packets. the code-group mapping is defined in table 1. scrambler/descrambler the 4b/5b encoded data has repetitive patterns which result in peaks in the rf spectrum large enough to keep the system from meeting the standards set by regulatory agencies such as the fcc. the peaks in the radiated signal are reduced significantly by scrambling the transmitted signal. scramb lers add the output of a random generator to the data signal. the resulting signal has fewer repetitive data patterns. after reset, the scrambler se ed in each port will be set to the phy address value to help improve the emi performance of the device. the scrambled data stream is descrambled, at the re- ceiver, by adding it to the output of another random generator. the receiver?s random generator has the same function as the transmitter?s random generator. the scrambler/descrambler configuration is set by the scram_en pin and the en_scrm bit (register 24, bit 2). the scram_en pin is latched at the rising edge of the rst signal. the scrambler/descrambler can be enabled if scram_en latches above 2.0 v. otherwise, they are all disabled. t he en_scrm bit sets the scrambler/descrambler configuration for the corre- sponding port. the bit defaults to 1 at reset. the scrambler/descrambler can only be enabled when the port is in the 100-mbps mlt-3 mode. the scrambler is disabled on any port that has a link at 10 mbps or any port that is forced to 10 mbps. link monitor signal levels are qualified us ing squelch detect circuits. a signal detect (sd) circui t following the equalizer is asserted high whenever the peak detector detects a post-equalized signal with peak-to-ground voltage level larger than 400 mv, which is about 40% of the normal signal voltage level, and the energy level is sustained longer than 2 ~ 3 ms. it is deasserted approximately 1 ms to 2 ms after the energy level detected in the re- ceiving lines is consistent ly less than 300 mv peak. the signal is forced to low during a local loopback op- eration (register 0, bit 14 loopback is asserted) and forced to high when a remote loopback is taking place (register 24, bit 3 en_rpbk is set). in 100base-tx mode, when no signal or invalid sig- nals are detected on the receive pair, the link monitor will enter in the ?link fail? state where only link pulses will be transmitted. otherwise, when a valid signal is detected for a minimum period of time, the link monitor will then enter link pass state which transmit and receive functions will be entered. am79c875 17 table 1. code-group mapping in 100base-fx mode, the external fiber-optic receiver performs the signal energy detection function and com- municates this in formation directly to the netphy? 4lp device through sdi pins. in 10base-t mode, a link-pul se detection circuit will constantly monitor the rx pins for the presence of valid link pulses. 10base-t block the netphy? 4lp transceiver incorporates four fully independent 10base- t physical layer functions, in- cluding clock recovery (endec), maus, and trans- ceiver functions. the netphy? 4lp transceiver receives 10-mbps data from the mac, switch, or re- peater across the rmii at 5 million di-bits per second. it then manchester encodes the data before transmis- sion to the network. mii (txd[3:0]) name pcs co de-group interpretation 0 0 0 0 0 1 1 1 1 0 data 0 0 0 0 1 1 0 1 0 0 1 data 1 0 0 1 0 2 1 0 1 0 0 data 2 0 0 1 1 3 1 0 1 0 1 data 3 0 1 0 0 4 0 1 0 1 0 data 4 0 1 0 1 5 0 1 0 1 1 data 5 0 1 10 6 0 1 1 1 0 data 6 0 1 1 1 7 0 1 1 1 1 data 7 1 0 0 0 8 1 0 0 1 0 data 8 1 0 0 1 9 1 0 0 1 1 data 9 1 0 1 0 a 1 0 1 1 0 data a 1 0 1 1 b 1 0 1 1 1 data b 1 1 0 0 c 1 1 0 1 0 data c 1 1 0 1 d 1 1 0 1 1 data d 1 1 1 0 e 1 1 1 0 0 data e 1 1 1 1 f 1 1 1 0 1 data f undefined i 1 1 1 1 1 idle; used as inter-stream fill code 0 1 0 1 j 1 1 0 0 0 start-of-stream delimiter, part 1 of 2; always used in pairs with k 0 1 0 1 k 1 0 0 0 1 start-of-stream delimiter, part 2 of 2; always used in pairs with j undefined t 0 1 1 0 1 end-of-stream delimiter, part 1 of 2; always used in pairs with r undefined r 0 0 1 1 1 end-of-stream delimiter, part 2 of 2; always used in pairs with t undefined h 0 0 1 0 0 transmit error; used to force signaling errors undefined v 0 0 0 0 0 invalid code undefined v 0 0 0 0 1 invalid code undefined v 0 0 0 1 0 invalid code undefined v 0 0 0 1 1 invalid code undefined v 0 0 1 0 1 invalid code undefined v 0 0 1 1 0 invalid code undefined v 0 1 0 0 0 invalid code undefined v 0 1 1 0 0 invalid code undefined v 1 0 0 0 0 invalid code undefined v 1 1 0 0 1 invalid code 18 am79c875 the 10base-t block cons ists of the following sub-blocks: ? transmit function ? receive function ? interface status ? jabber function ? reverse polarity detect refer to figure 5 for the 10base-t transmit and receive data paths. figure 5. 10base-t transmit/receive data paths twisted pair transmit function data transmission over the 10base-t medium re- quires use of the integr ated 10base-t mau and uses the differential driver circuitry on the tx pins. tx is a differential twisted-pair driver. when properly terminated, tx meets the transmitter electrical re- quirements for 10base-t trans mitters as specified in ieee 802.3, section 14.3.1.2. the load is a twisted pair cable that meets ieee 802.3, section 14.4. the tx signal is filtered on the chip to reduce har- monic content per section 14.3.2.1 (10base-t). since filtering is performed in silicon, tx can be connected directly to a standard transformer. external filtering modules are not needed. twisted pair receive function rx+ ports are differential twisted-pair receivers. when properly terminated, each rx+ port meets the electrical requirements for 10base-t re ceivers as specified in ieee 802.3, section 14.3.1 .3. each receiver has internal filtering and does not require external filter modules or common mode chokes. signals appearing at the rx differential input pair are routed to the internal decoder. the receiver function meets the propagation delays and jitter requirements specified by the 10base-t standard. the receiver squelch level drops to half its threshold value after un- squelch to allow reception of minimum amplitude sig- nals and to mitigate carrier fade in the event of worst case signal attenuation and crosstalk noise conditions. twisted pair interface status the netphy? 4lp transceiver will power up in the link fail state. the auto-negotiation algorithm will apply to allow it to enter the link pass state. in the link pass state, receive activity which passes the pulse width/amplitude requirements of the rx inputs cause the pcs control block to assert carrier sense (crs) signal at the mii interface. jabber function the jabber function inhibits the 10base-t twisted pair transmit function of the netphy? 4lp transceiver de- vice if the tx circuits ar e active for an excessive pe- riod (20-150 ms). this prevents one port from disrupting the network due to a stuck-on or faulty trans- mitter condition. if the maxi mum transmit time is ex- ceeded, the data path through the 10base-t transmitter circuitry is disabled (although link test pulses will continue to be se nt). the pcs control block also sets the jabber detect bit in register 1. once the internal transmit data stream from the mendec stops, an unjab time of 250-750 ms will elapse before this block causes the pcs control block to re-enable the transmit circuitry. when jabber is detected, this block allows the pcs control block to assert or de-assert the crs pin to in- dicate the current state of the rx pair. if there is rx activity, this block causes the pcs control block to as- sert crs at the rmii. the jabber function can be dis- abled by setting register 24, bit 12. reverse polarity detect and correction proper 10base-t rece iver operation requires that the differential input signal be the correct polarity. that is, the rx+ line is connected to the rx+ input pin, and the rx- line is connected to the rx- input pin. improper setup of the external wiring can cause the polarity to be reversed. the netphy? 4lp receivers have the ability to detect the polarity of the incoming signal and com- pensate for it. thus , the proper signa l will appear on the mdi regardless of the polarity of the input signals. the internal polarity detection and correction circuitry is set during the reception of the normal link pulses (nlp) or packets. the receiver detects the polarity of the input clock data manchester encoder clock data manchester decoder squelch circuit rx driver rx tx tx driver loopback (register 0) 22236g-7 am79c875 19 signal on the first nlp. it locks the polarity correction circuitry after the reception of two consecutive packets. the state of the polarity correction circuitry is locked as long as link is established. this function is only avail- able in 10base-t mode. far-end fault indication (fefi) auto-negotiation provides a remote fault capability for detecting an asymmetric link failure. since 100base-fx systems do not use auto-negotiation, an alternative, in-band signaling scheme is used to signal remote fault conditions. this scheme, far end fault in- dication, relies on the charac teristics of the quiescent state, a continuous idle st ream. the idle stream is a continuous stream of logic ones followed by one logic zero, with the pattern re peated at least 3 times. a far-end fault will be si gnaled under the following three conditions: (1) when no activity is received from the link partner, since this can indicate a broken receive wire, (2) when the clock recovery circuit detects a receive signal error or pll lock error, (3) when man- agement entity sets the transmit far-end fault bit (register 24, bit 7). the far-end fault mechanism defaults to enabled in 100base-fx mode and disabled in 100base-tx and 10base-t modes, and may be controlled by software after reset. mlt-3 this block is responsible for converting the nrzi data stream from the pdx block to the mlt-3 encoded data stream. the effect of mlt-3 is the reduction of energy on the copper media (tx or fx cable) in the critical frequency range of 1 mhz to 100 mhz. the receive section of this block is responsible for equalizing and amplifying the received data stream and link detection. the adaptive equalizer compensates for the amplitude and phase distortion due to the cable. mlt-3 is a tri-level signal. all transitions are between 0 v and +1 v or 0 v and -1 v. a transition has a logical value of 1 and a lack of a transition has a logical value of 0. the benefit of mlt-3 is that it reduces the maxi- mum frequency over the data line. the bit rate of tx data is 125 mbps. the maximum frequency (using nrzi) is half of 62.5 mhz. mlt-3 reduces the maxi- mum frequency to 31.25 mhz. a data signal stream followi ng mlt-3 rules is illustrated in figure 6. the data stream is 1010101. figure 6. mlt-3 waveform the tx drivers convert the nrzi serial output to mlt-3 format. the rx receivers convert the received mlt-3 signals to nrzi. the transmit and receive sig- nals will be compliant with ieee 802.3u, section 25. the required signals (mlt-3) are described in detail in ansi x3.263:1995 tp-pmd revision 2.2 (1995). the netphy? 4lp device provides on-chip filtering. external filters are not required for either the transmit or receive signals. the tx pins can be connected to the media via either a 1:1 transformer or a 1.25:1 transformer. the 1.25:1 ratio provides a 20% transmit power savings over the 1:1 ratio. refer to figure 7. adaptive equalizer the netphy? 4lp device is designed for the maxi- mum of 140 meter utp-5 cable. a 140-meter utp-5 cable attenuates the signal by 32 db at 100 mhz which far exceed the cable plant attenuation (24-26 db) de- fined by tp-pmd. the amplitude and phase distortion from cable causes inter-symbol interference (isi) which makes clock and data recovery impossible . adaptive equalization is done by closely matching the characteristics of the twisted-pair cable. this is a variable equalizer which changes equalizer frequency response in accordance with cable length. the cable length is estimated based on comparisons of incoming signal strength against some known cable characteristics. the equalizer tunes itself automatically to the any cable length to compen- sate for the amplitude and phase distortion incurred from the cable. baseline wander compensation the 100base-tx data stream is not always dc bal- anced. the media, with transformer and common mlt-3 1010101 8 ns 22236g-8 20 am79c875 mode filtering blocks the dc component of the code and the dc offset of the differential receive input can wander. the shift in the signal levels causes increase in error rates. a dc restoration circuit is needed to compensate for the attenuation of dc components. the netphy? 4lp device implemented a patent- pending dc restoration circuit which, unlike the tra- ditional implementation, does not need the feedback information from the slicer and clock recovery. the baseline wander correction circuit is not required and, therefore, is bypassed when the port is 10base-t. clock/data recovery the equalized mlt-3 signal is converted into nrzi for- mat. the netphy? 4lp device uses an analog phase locked loop (apll) to extract clock information of the incoming nrzi data which is used to re-time the data stream and set data boundaries. the receive clocks are locked to the incoming data streams. ppm should be between 50 and 100. when initial lock is achi eved, the apll switches to lock-to-data stream, extracts a 125-mhz clock. the re- covered 125 mhz clock is also used to generate the 25- mhz rx_clk. the apll requires no external compo- nents for its operation and has high noise immunity and low jitter. it provides fast phase align (lock) to data in one transition and its data/clo ck acquisition time after power-on is less than 60 transitions. the apll can maintain lock on run-lengths of up to 60 data bits in the absence of signal transitions. when no valid data is present, the apll switches back to lock with the tx_clk, providing a continuously running rx_clk. the recovered data is converted from nrzi-to-nrz and then to a 5-bit parallel format. the 5-bit parallel data is not necessarily aligned to 4b/5b code-group?s symbol boundary. the data is presented to pcs at re- ceive data register output, gated by the 25-mhz rx_clk. figure 7. tx and rx termination for 100base-tx and 10base-t tx+ tx? sdi/mlt3en rx+ rx? tx+ (1) rx+ (3) tx? (2) rx? (6) rj45 connector isolation transformer with common-mode chokes 50 50 0.1 f 470 pf 75 75 75 75 * 1:1 * * 1:1 or 1.25:1 * (8) (7) (5) (4) (chassis ground) (chassis ground) 1 k (note 3) (note 3) v dd 0.1 f 0.1 f 470 pf (note 4) (note 4) 22236g-9 notes: 2. the isolation transformers include common-mode chokes. 3. consult magnetics vendors for appropriate termination schemes. 4. 50 if a 1:1 isolation transformer is used or 78 if a 1.25:1 isolation transformer is used. 5. 50 (49.9) is normal, but 54.9 can be used for extended cable length operation. am79c875 21 auto-negotiation and miscellaneous functions auto-negotiation the object of the auto-negot iation function is to deter- mine the abilities of the devi ces sharing a link. after ex- changing abilities, the netphy? 4lp device and remote link partner device acknowledge each other and make a choice of which advertised abilities to sup- port. the auto-negotiation function facilitates an or- dered resolution between exchanged abilities. this exchange allows both devices at either end of the link to take maximum advantage of their respective shared abilities. the netphy? 4lp device implements the transmit and receive auto-negotiation algorithm as defined in ieee 802.3u, section 28. the auto-negotiation algo- rithm uses a burst of link pul ses called fast link pulses (flp). the burst of link pulses are spaced between 55 and 140 s so as to be ignored by the standard 10base-t algorithm. the fl p burst conveys informa- tion about the abilities of the sending device. the receiver can accept and decode an flp burst to learn the abilities of the sendin g device. the link pulses transmitted conform to the standard 10base-t tem- plate. the netphy? 4lp device can perform auto- negotiation with reverse polarity link pulses. the netphy? 4lp device supports next page advertise- ment. the netphy? 4lp device uses the auto-negotiation algorithm to select the type connection to be estab- lished according to the fo llowing priority: 100base-tx full duplex, 100base-t4, 1 00base-tx half-duplex, 10base-t full duplex, 10base-t half-duplex. the device does not suppor t 100base-t4 connections. the auto-negotiation algorithm is initiated when one or the following events occurs : auto-negotiation enable bit is set, or reset, or soft reset, or transition to link fail state (when auto-negotiation enable bit is set), or auto-negotiation restart bit is set. the result of the auto- negotiation process can be read from the sta- tus register for the port of interest (diagnostic register, register 18). the netphy? 4lp device supports parallel detection for remote legacy devices that do not support the auto- negotiation algorithm. in the case that a 100base-tx only device is connected to the remote end, the net- phy? 4lp device will see scr ambled idle symbols and establish a 100base-tx only connection. if nlps are seen, the netphy? 4lp device will establish a 10base-t connection. loopback operation a local loopback and a remote loopback are provided for diagnostic testing. loc al loopback can be achieved by writing to register 0, bit 14 (lpbk). remote loop- back can be achieved by writing to register 24, bit 3. the local loopback routes transmitted data at the out- put of the nrz-to-nrzi conversion module back to the receiving path?s clock and data recovery module for connection to pcs in 5-bit symbol format. this loop- back is used to check all the device?s connection at the 5-bit symbol bus side and the operation of the analog phase locked loop. in the local loopback mode, the sdi output is forced to high and the tx outputs are tri-stated. the remote loopback routes receiving data at the out- put of the clock and data recovery module to the trans- mitting path?s nrzi-to-mlt-3 conversion module. this loopback is used to check the device?s connection on the media side and the operation of its internal adaptive equalizer, digital phase locked loop, and digital wave shape synthesizer. during the remote loopback mode, the sdi output is forced to low. power savings mechanisms the netphy? 4lp device has three mechanisms for reducing power: selectable 1.25:1 transmit transformer ratio, unplugged, and power down. selectable transformer the tx outputs can drive either a 1:1 transformer or a 1.25:1 transformer. the latter can be used to reduce transmit power further. the tp1_1 pin must be pulled low at reset to select 1.25:1 transformers. the current at the tx pins for a 1:1 ratio transformer is 40 ma for mlt-3 and 100 ma for 10 base-t. using the 1.25:1 ratio reduces the current to 32 ma for mlt-3 and 80 ma for 10base-t. the cost of using the 1.25:1 option is in impedance coupling. the reflected capacitance is increased by the square of the ratio of windings (1.25 2 = 1.56). thus, the reflected capacitance on the media side is roughly 1? times the capacitance on the board. extra care in the layout to control capa citance on the board is re- quired. unplugged the unplugged feature reduces power consumption whenever the phy is operating. the tx output drivers limit the drive capability if the corresponding receivers do not detect a link partner within 4 seconds. this pre- vents ?wasted? power. if the receiver detects the ab- sence of a link partner, the corresponding transmitter is limited to transmitting normal link pulses. any energy detected by the receiver ena bles full transmit capabili- ties. a typical situation encountered is that most un- used ports still consume powe r. up to 25% of repeater and switch ports are unconnected to allow room for fu- ture expansion. with netphy? 4lp, unconnected ports have their receiver disabled until energy is de- tected. the power savings is most notable on uncon- 22 am79c875 nected ports and ports running at 10 or 100 mbps with auto-negotiation disabled. typical power becomes 100 mw per port. power down most of the netphy? 4lp device can be disabled via the power down bit in register 0, bit 11. setting this bit on register 0 of any port will power down the respec- tive port with the exception of the mdio/mdc manage- ment circuitry. typical power becomes 5 mw or lower per port. led port configuration the netphy? 4lp device has several pins that are used for both device configuration and led drivers. these pins set the configuration of the device on the rising edge of rst and thereafter indicate the state of the respective port. see table 2. the polarity of the led driv ers (active-low or active- high) is set at the rising edge of rst . if the pin is low at the rising edge of rst , it becomes an active-high driver. if it is high at the rising edge of rst , it becomes an active-low driver. proper configuration requires external pull-up or pull- down resistors. if the led co rresponding to a pin is not used, the pin must be terminated via a resistor. the re- sistor value is not critical and can be in the range of 1 k to 4.7 k . if the corresponding led is used, the terminating resistor must be placed in parallel with the led. figure 8 illustrates the wiring of the leds for both configuration settings. the value of the series resistor (r l ) should be selected to ensure sufficient illu mination of the led. it is dependent on the rating of the led. table 2. led display configuration notes: 1. n = phy port number (0...3) 2. x = don?t care note: ledxxx/xxx = any led pin. figure 8. led port configuration ledact_link[n] ledspd[n] leddpx[n] cable connected (link) led on led off led off 100mbps, half duplex led on led on led off 100mbps, full duplex led on led on led on 10mbps, half duplex led on led off led off 10mbps, full duplex led on led off led on rmii mode: activity blinks on transmit/receive activity x x ledxxx/xxx configure low with an active-high led 1 - 4.7 k ledxxx/xxx configure high with an active-low led v r l r l dd 1 - 4.7 k 22236g-10 am79c875 23 phy control and management block (pcm block) register administration for 100base-x phy device the management interface specified in clause 22 of the ieee 802.3u standard provides for a simple two wire, serial interface to connect a management entity and a managed phy for the pu rpose of controlling the phy and gathering status information. the two lines are management data input/output (mdio) and management data clock (mdc). a station manage- ment entity which is attach ed to multiple phy entities must have prior knowledge of the appropriate phy ad- dress for each phy entity. description of the methodology the management interface physically transports man- agement information across the rmii. the information is encapsulated in a frame format as specified in clause 22 of ieee 802.3u dr aft standard and is shown in table 3. table 3. clause 22 management frame format the phyad field, which is five bits wide, allows 32 unique phy addresses. the managed phy layer de- vice that is connected to a station management entity via the mii interface has to respond to transactions addressed to the phy's address. a station manage- ment entity attached to multiple phys, such as in a managed 802.3 repeater or ethernet switch, is re- quired to have prior knowledge of the appropriate phy address. setting the phyad bits the phyad of each port is the combination of the set- ting of the netphy? 4lp device and the port number. the netphy? 4lp device is set by phyad[4:2] at the rising edge of rst . the lower two bits of the phyad are set by the individual ports in the phy. if the phyad[4:2] is set to 010, the phyad of each port is as follows: port 0 01000 port 1 01001 port 2 01010 port 3 01011 section 22 of the ieee 802.3 standard states that all phy devices connected to a mechanical interface will respond to phyad ?00000? command regardless of the actual address of the phy. there are applications where it is necessary to avoid setting the phyad of a port to ?00000.? the netp hy? 4lp contains a mecha- nism that allows the phyads to be shifted by 1. the phyad_st pin enables this mechanism. if the pin is low at power-up, the phyads are incremented by 1. to set the phyad pins, use pull-up or pull-down resis- tors in the range of 1 k to 4.7 k . if phyad is set to 000, the address of each port is as follows: port 0 00001 port 1 00010 port 2 00011 port 3 00100 the address shifting carries over the entire address space. if phyad[4:2] is set to 111, the phyad for each port is as follows: port 0 11101 port 1 11110 port 2 11111 port 3 00000 table 4. phy address setting frame structure pre st op phyad regadd ta data idle read 1.1 01 10 aaaaa rrrrr z0 d...........d z write 1.1 01 01 aaaaa rrrrr 10 d...........d z pre st op phyad regadd ta data idle read 1.1 01 10 00000 rrrrr z0 xxxxxxxxxppaaaaa z write 1.1 01 01 00000 rrrrr 10 xxxxxxxxxppaaaaa z 24 am79c875 figure 9. phy management read and write operations bad management frame handling the management block of the device can recognize management frames without preambles (preamble suppression). however, if it receives a bad manage- ment frame, it will go into a bad management frame state. it will stay in this state and will not respond to any management frame without preambles until a frame with a full 32-bit preamble is received, then it will return to normal operation. a bad management frame is a frame that does not comply with the ieee standard specification. it can be one with less than 32-bit pr eamble, with illegal op field, etc. however, a frame with more than 32 preamble bits is considered to be a good frame. table 5. netphy? 4lp mii management register set idl e st ar t opcod e ( rea d) phy a dd re ss 16h, po r t 2 regi st er a dd re ss mii st a tus, 1h t a regi st er d a t a idl e z z z mdc mdio (phy) mdio (st a ) z z 01101011000001 00110000 01000001 0 z z read operation idl e st ar t opcod e ( wri t e ) phy a dd re ss 16h, po r t 2 regi st er a dd re ss mii co n t r ol, 0h t a regi st er d a t a idl e z z mdc mdio (st a ) z 0101101100000010011000 100000000 0 z write operation 22236g-11 register address (in decimal) description 0 mii management control register 1 mii management status register 2 phy identifier 1 register 3 phy identifier 2 register 4 auto-negotiation advertisement register 5 auto-negotiation link partner ability register 6 auto-negotiation expansion register 7 next page advertisement register 8-15 reserved 16 miscellaneous features register 17 interrupt control/status register 18 diagnostic register 19 test register 20 miscellaneous features 2 21 receiver error counter 22 reserved 23 reserved 24 mode control register 25-31 reserved am79c875 25 the physical address of th e phy is set using the pins defined as phyad[4:2]. these input signals are strapped externally and sampled as reset is negated. the phyad[1:0] will be decoded by the netphy? 4lp device to address its inte rnal four phy channels. all registers are available on a per port basis. table 6. legend for register tables type description rw readable and writable sc self clearing ll latch low until clear ro read only rc cleared on the read operation lh latch high until clear 26 am79c875 mii management control register (register 0) table 7. mii management control register (register 0) reg bit name description read/ write default 0 15 reset 1 = phy reset. 0 = normal operation. this bit is self-clearing. rw/sc 0 0 14 loopback 1 = enable loopback mode. this will loopback txd to rxd, thus it will ignore all the activity on the cable media. 0 = disable loopback mode. normal operation. rw 0 0 13 speed select 1 = 100 mbps. 0 = 10 mbps. rw set by force100 pin 0 12 auto-neg enable 1 = enable auto-negotiation process (overrides 0.13 and 0.8). 0 = disable auto-negotiation process. rw set by anega pin 0 11 power down 1 = power down. the netphy? 4lp device will shut off all blocks except for mdio/mdc interface. 0 = normal operation. rw 0 010 isolate 1 = electrically isolate the phy from mii. however, phy is still able to respond to mdc/mdio. 0 = normal operation. rw 0 09 r e s t a r t auto-negotiation 1 = restart auto-negotiation process. 0 = normal operation. rw/sc 0 0 8 duplex mode 1 = full duplex. 0 = half duplex. auto-negotiation enabled: this bit is writable but will be ignored. auto-negotiation disabled: this pin is reset read value of dplx. rw set by dplx pin 0 7 collision test 1 = enable collision test, which issues the col signal in response to the assertion of tx_en signal. collision test is enabled regardless of the duplex mode. 0 = disable col test. rw 0 0 6:0 reserved write as 0, ignore on read. rw 0 am79c875 27 mii management status register (register 1) table 8. mii management status register (register 1) reg bit name description read/ write default 1 15 100base-t4 1 = 100base-t4 able. 0 = not 100base-t4. ro 0 114 100base-tx full duplex 1 = 100base-tx with full duplex. 0 = no 100base-tx fu ll duplex ability. ro set by dplx pin 113 100base-tx half duplex 1 = 100base-tx with half duplex. 0 = no 100base-tx half-duplex ability. ro 1 112 10base-t full duplex 1 = 10base-t with full duplex. 0 = no 10base-t full duplex ability. ro set by dplx pin 111 10base-t half duplex 1 = 10base-t with half duplex. 0 = no 10base-t half duplex ability. ro 1 1 10:7 reserved ignore when read. ro 0 16 mf preamble suppression 1 = phy can accept manageme nt (mgmt) frames with or without preamble. 0 = phy can only accept mgmt frames with preamble. ro 1 15 auto-negotiation complete 1 = auto-negotiation process co mpleted. registers 4, 5, 6 are valid after this bit is set. 0 = auto-negotiation process not completed. ro 0 1 4 remote fault 1 = remote fault condition detected. 0 = no remote fault. this bit will remain set until it is cleared by reading register 1 via management interface. ro/lh 0 13 auto-negotiation ability 1 = able to perform auto-negotiation function, its value is determined by anega pin. 0 = unable to perform auto-negotiation function. ro set by anega pin 1 2 link status 1 = link is established, however, if the netphy? 4lp device link fails, this bit will be cleared and remain cleared until register is read via management interface. 0 = link is down. ro/ll 0 1 1 jabber detect 1 = jabber condition detect. 0 = no jabber condition detected. ro/lh 0 10 extended capability 1 = extended register capable. this bit is tied permanently to one. ro 1 28 am79c875 phy identifier 1 register (register 2) table 9. phy identifier 1 register (register 2) phy identifier 2 register (register 3) table 10. phy identifier 2 register (register 3) auto-negotiation advertisement register (register 4) table 11. auto-negotiation advertisement register (register 4) reg bit name description read/ write default 2 15:0 oui composed of the 3rd through 18th bits of the organizationally unique identifier (o ui), respectively. ro 0022(h) reg bit name description read/ write default 3 15:10 oui assigned to the 19th through 24th bits of the oui. ro 010101 3 9:4 model number six bit manufacturer?s model number. ro 010100 3 3:0 revision number four bit manufacturer?s revision number. 0001 stands for rev. a, etc. ro 0001 reg bit name description read/ write default 415 next page 1 = next page enabled. 0 = next page disabled. rw 0 4 14 acknowledge this bit will be set internally after receiving 3 consecutive and consistent flp bursts. ro 0 4 13 remote fault 1 = remote fault supported. 0 = no remote fault. rw 0 4 12:11 reserved write as 0, ignore when read. rw 0 410 fdfc full duplex flow control. 1 = advertise that the dte(ma c) has implemented both the optional mac control sublayer and the pause function as specified in clause 31 and annex 31 b of 802.3u. 0 = no mac-based full duplex flow control. rw 0 4 9 100base-t4 the netphy? 4lp device does not support 100base-t4 function, i.e., this bit ties to zero. ro 0 48 100base-tx full duplex 1 = 100base-tx with full duplex. 0 = no 100base-tx full duplex ability. default is set by register 1.14. rw set by dplx pin 47 100base-tx half duplex 1 = 100base-tx with half duplex. 0 = no 100base-tx half duplex capability. default is set by register 1.13. rw 1 46 10base-t full duplex 1 = 10 mbps with full duplex. 0 = no 10mbps full duplex capability. default is set by register 1.12. rw set by dplx pin 45 10base-t half duplex 1 = 10 mbps with half duplex. 0 = no 10 mbps half duplex capability default is set by register 1.11. rw 1 4 4:0 selector field [00001] = ieee 802.3 ro 00001 am79c875 29 auto-negotiation link partner ability register in base page format (register 5) table 12. auto-negotiation link partner ability register in base page format (register 5) auto-negotiation link partner ability register in next page format (register 5) table 13. auto-negotiation link partner ability register in next page format (register 5) reg bit name description read/ write default 5 15 next page 1 = next page requested by link partner. 0 = next page not requested. ro 0 5 14 acknowledge 1 = link partner acknowledgement. 0 = no link partner acknowledgement. ro 0 5 13 remote fault 1 = link partner remote fault request. 0 = no link partner remote fault request. ro 0 5 12:11 reserved reserved for future technology ro 5 10 flow control 1 = link partner supports flow control. 0 = link partner does not support flow control. ro 0 5 9 100base-t4 1 = remote partner is 100base-t4 capable. 0 = remote partner is not 100base-t4 capable. ro 0 58 100base-tx full duplex 1 = link partner is capable of 100base-tx with full duplex. 0 = link partner is not capable of 100base-tx with full duplex ro 0 57 100base-tx half duplex 1 = link partner is capabl e of 100base-tx with half duplex. 0 = link partner is not capable of 100base-tx with half duplex ro 0 56 10base-t full duplex 1 = link partner is cap able of 10base-t with full duplex. 0 = link partner is not capable of 10base-t with full duplex ro 0 55 10base-t half duplex 1 = link partner is cap able of 10base-t with half duplex. 0 = link partner is not ca pable of 10base-t with half duplex. ro 0 5 4:0 selector field link partner selector field. ro 0 reg bit name description read/ write default 5 15 next page 1 = next page requested by link partner. 0 = next page not requested. ro 0 5 14 acknowledge 1 = link partner acknowledgement. 0 = no link partner acknowledgement. ro 0 5 13 message page 1 = link partner message page request. 0 = no link partner message page request. ro 0 5 12 acknowledge 2 1 = link partner can comply with next page request. 0 = link partner cannot comply with next page request. ro 0 5 11 toggle link partner toggle. ro 0 5 10:0 message field link partner?s message code. ro 0 30 am79c875 auto-negotiation expansion register (register 6) table 14. auto-negotiation expansion register (register 6) auto-negotiation next page advertisement register (register 7) table 15. auto-negotiation next page advertisement register (register 7) reserved registers (registers 8-15, 22-23, 25-31) the netphy? 4lp device contains reserved registers at addresses 8-15, 22-23, 25-31. these registers should be ignored when read and should not be written at any time. reg bit name description read/ write default 6 15:5 reserved ignore when read. ro 0 64 parallel detection fault 1 = fault detected by parallel detection logic, this fault is due to more than one technology detecting concurrent link up condition. this bit can only be cleared by reading this register via management interface. 0 = no fault detected by parallel detection logic. ro/lh 0 63 link partner next page able 1 = link partner support next page function. 0 = link partner does not support next page function. ro 0 6 2 next page able next page is supported, i.e ., this bit is permanently ties to 1. ro 1 6 1 page received it is set when a new link code word has been received into the auto-negotiation link partner ability register. this bit is cleared upon a read of this register. ro/lh 0 60 link partner auto- negotiation able 1 = link partner is auto-negotiation able. 0 = link partner is not auto-negotiation able ro 0 reg bit name description read/ write default 715 np next page indication: 1 = another next page desired. 0 = no other next page transfer desired rw 0 7 14 reserved ignore when read. ro 0 713 mp message page: 1 = message page 0 = un-formatted page. rw 1 712 ack2 acknowledge 2 1 = will comply with message. 0 = cannot comply with message. rw 0 711 tog_tx to g g l e : 1 = previous value of transmitted link code word equals to 0 0 = previous value of transmitted link code word equals to 1 rw 0 7 10:0 code message/un-formatted code field. rw 001 am79c875 31 miscellaneous features register (register 16) table 16. miscellaneous features register (register 16) interrupt control/status register (register 17) table 17. interrupt control/status register (register 17) reg bit name description read/ write default 16 15 reserved write as 0; 1 = factory use only. rw 0 16 14 intr_levl 1 = int is forced to 1 to signal an interrupt. 0 = int is forced to 0 to signal an interrupt. rw 0 16 13 txjam 1 = force cim to send jam pattern. 0 = normal operation mode. ro 0 16 12:4 reserved write as 0, ignore when read. rw 00000 16 3:0 reserved ignore when read. ro 0 reg bit name description read/ write default 17 15 jabber_ie jabber interrupt enable. rw 0 17 14 rx_er_ie receive error interrupt enable. rw 0 17 13 page_rx_ie page received interrupt enable. rw 0 17 12 pd_fault_ie parallel detect ion fault interrupt enable. rw 0 17 11 lp_ack_ie link partner acknowledge interrupt enable. rw 0 17 10 link_not_ok_ ie link status not ok interrupt enable. rw 0 17 9 r_fault_ie remote fault interrupt enable. rw 0 17 8 aneg_comp_ie auto-negotiation complete interrupt enable. rw 0 17 7 jabber_int this bit is set when a jabber event is detected. rc 0 17 6 rx_er_int this bit is set when rx_er transitions high. rc 0 17 5 page_rx_int this bit is set when a new page is received from link partner during auto-negotiation. rc 0 17 4 pd_fault_int this bit is set when parallel detect fault is detected. rc 0 17 3 lp_ack_int this bit is set when the flp with acknowledge bit set is received. rc 0 17 2 link_not_ok int this bit is set when link status s witches from ok status to non-ok status (fail or ready). rc 0 17 1 r_fault_int this bit is set when remote fault is detected. rc 0 17 0 a_neg_comp int this bit is set when auto-negotiation is complete. rc 0 32 am79c875 diagnostic register (register 18) table 18. diagnostic register (register 18) test register (register 19) table 19. test register (register 19) miscellaneous features 2 register (register 20) table 20. miscellaneous features 2 register (register 20) reg bit name description read/ write default 18 15:12 reserved ignore when read. ro 0 18 11 dplx this bit indicates the result of the auto-negotiation for duplex arbitration. 1 = full duplex. 0 = half duplex. ro 0 18 10 speed this bit indicates the result of the auto-negotiation for data speed arbitration. 1 = 100 mbps. 0 = 10 mbps. ro 0 18 9 rx_pass in 10base-t mode, a 1 indicates that manchester data has been detected. in 100base-tx mode, a 1 indica tes a valid signal has been received but not necessarily locked onto. ro 0 18 8 rx_lock 1 = received rll has locked onto the received signal for selected data-rate (10base-t or 100base-tx) 0 = receive pll has not locked onto received signal. this bit remains set until read. ro/rc 0 18 7:0 reserved ignore when read. ro 0x22 reg bit name description read/ write default 19 15:12 reserved ignore when read, writ e as default (0x1000). rw 0x1000 19 11:8 reserved ignore when read, writ e as default (0x0010). rw 0x0010 19 7 reserved ignore when read, write as 0. rw 0 19 6 1.25:1 selects transformer ratio. 1 = 1.25:1 0 = 1:1 the default value is controlled by the tp1_1 pin. rw 0 19 5 10/100 mbps transmit compliance test this bit controls internal logic, including power-saving circuitry. for 10 and 100 mbps transmit compliance testing only, this bit must be turned off, but should be turned on for normal operation. the default is 1 (on). 1 = normal operation. 0 = compliance test mode. rw 1 19 4:0 reserved ignore when read, write as 0. rw 0 reg bit name description read/ write default 20 15:12 reserved ignore when read, write as default (0x0110). rw 0x0110 20 11:8 reserved ignore when read, write as default (0x1001). rw 0x1001 20 7:4 cable length indicator these bits are the cable length indicators. increment from 0000 to 1111, or approximately every 10 meters. the equivalent is 0 to 32db with an increment of 2db @ 100mhz. the value is read back from the equalizer, and the measured value is not absolute. ro 0 20 3:0 reserved ignore when read. ro 0x0010 am79c875 33 receive error counter (register 21) table 21. receive error counter (register 21) mode control register (register 24) table 22. mode control register (register 24) reg bit name description read/ write default 21 15:0 rx_er counter count of receive error events. rw 0000 (hex) reg bit name description read/ write default 24 15 sdcm_sel select common mode voltage setting for fx signal detect (sdi) input signal. 1 = select internal common mode setting. 0 = select external common voltage setting. rw 0 24 14 force 10base-t link up 1 = force link up at 10 mbps without checking nlp. auto- negotiation must be disabled and the data rate must be 10 mbps. 0 = normal operation. rw 0 24 13 force 100base-tx link up 1 = force link up at 100 mbps. auto-negotiation must be disabled and the data rate must be 100 mbps. 0 = normal operation. rw 0 24 12 jabber disable 1 = disable jabber function in phy. 0 = enable jabber function in phy. rw 0 24 11 reserved write as 0, ignore when read. rw 0 24 10 activity led configuration 1 = activity only responds to receive operation. 0 = activity responds to receive and transmit. in repeater mode, this bit will be ignored. rw 1 24 9 reserved write as 0, ignore when read. rw 0 24 8 fefi_disable set this bit will disable fefi gener ation and detection function. the default value of this bit is 0 when the chip is working in fx mode. otherwise the default value is 1. rw set by fx_dis and anega pins 24 7 force fefi transmit this bit is set to force the transmit fefi pattern. rw 0 24 6 rx_er_cnt full this bit is set to one to indicate the receive error counter is full. ro/rc 0 24 5 disable rx_er counter 1 = disable receive error counter. rw 0 24 4 dis_wdt 1 = disable the watchdog timer in the decipher. rw 0 24 3 en_rpbk 1 = enable remote loopback, 0 = disable remote loopback. rw 0 24 2 en_scrm 0 = disable data scrambling. 1 = enable data scrambling. when fx_dis pin is asserted low or fx_sel bit (register 24.0) is set to logic high, this bit will be overwritten as ?1? automatically. the default of this bit is set by power on read value of fx_dis. rw set by scram_en pin 24 1 reserved write as 0, ignore when read. ro 0 24 0 fx_sel set this bit to logic 1 to select 100base-fx mo de, set to logic 0 to select 100base-tx. rw set by fx_dis pin 34 am79c875 a bsolute maximum ratings storage temperature . . . . . . . . . . . . .-55c to +150c ambient temperature under bias . . .-55c to +150c supply voltage (v dd) . . . . . . . . . . . . . -0.5 v to +5.5 v voltage applied to any input pin. . . . . . . -0.5 v to v dd stresses above those listed under absolute maximum ratings may cause permanent device failure. functionality at or above these limits is not implied. exposure to absolute maximum ratings for extended periods may affect device reliability. operating ranges commercial (c): operating temperature (ta) . . . . . . . . . 0c to +70c supply voltage (all v dd ) . . . . . . . . . . . . . . +3.3 v 5% supply voltage (5-v tolerant pins) . . . . . . +5.0 v 5% industrial (i): operating temperature (ta) . . . . . . . . -40c to +85c supply voltage (all v dd ) . . . . . . . . . . . . . . +3.3 v 5% supply voltage (5-v tolerant pins) . . . . . . +5.0 v 5% operating ranges define t hose limits between which functionality of the device is guaranteed. dc characteristics note: parametric values are the same for commercial and industrial devices. symbol parameter description test conditions minimum maximum units v il input low voltage 0.8 v v ih input high voltage 2.0 v v ol output low voltage i ol = 8 ma 0.4 v v oh output high voltage i oh = -4 ma 2.4 v v oll output low voltage (led) i ol (led) = 10 ma 0.4 v v ohl output high voltage (led) i ol (led) = -10 ma v dd ? 0.4 v v cmp input common-mode voltage pecl (note 1) v dd ? 1.5 v dd ? 0.7 v v idiffp differential input voltage pecl (note 1) v dd = maximum 400 1,100 mv v ohp output high voltage pecl (note 4) pecl load v dd ? 1.025 v dd ? 0.60 v v olp output low voltage pecl (note 4) pecl load v dd ? 1.81 v dd ? 1.62 v v sda signal detect assertion threshold peak-to-peak (note 2) mlt-3/10base-t test load - 1000 mv v sdd signal detect deassertion threshold peak-to-peak (note 3) mlt-3/10base-t test load 200 - mv i il input low current (note 5) v dd = maximum v in = 0.0 v -40 a i ih input high current (note 5) v in = v dd 40 a v txout differential output voltage (note 6) mlt-3/10base-t test load 950 1050 mv v txos differential output overshoot (note 6) mlt-3/10base-t test load - 0.05 * v txout v v txr differential output voltage ratio (note 6 & note 7) mlt-3/10base-t test load 0.98 1.02 - am79c875 35 power supply current consumption notes: 1. applies to fxr+, fxr-, sdi+, and sdi- inputs only. valid only when port 3 is in pecl mode. v dd is that of the fiber transceiver. 2. applies to rx inputs when the corresponding port is in mlt-3 mode only. the rx input is guaranteed to assert internal signal detect for any valid peak-to- peak input signal greater than v sda max. tested within limits of v sdd and v sda . 3. applies to rx inputs when the corresponding port is in mlt-3 mode only. the rx input is guaranteed to de-assert internal signal for any peak to peak signal less than v sdd min. tested within limits of v sdd and v sda . 4. applies to fxt+ and fxt- outputs only. valid only when port 3 is in pecl mode. v dd is that of the fiber transceiver. 5. applies to digital inputs and all bidirectional pins. rx limits up to 1.0 ma max for i il and -1.0 ma min for i ih . pull-up/pull-down resistors effect this value. 6. applies to tx differential outputs only. valid only when the port is in the mlt-3 mode. 7. v txr is the ratio of the magnitude of tx in the positive direction to the magnitude of tx in the negative direction. 8. parameter not tested. 9. only valid for tx out put when the port is in the 10base-t mode. 10. i oz applies to all high-impedance output pins. pull-up/pull-down resistors effect this value. 11. tested with all tx output pins driving the rated load. 12. assumes 80% utilization with all ports at 10 mbps, using 1:1 transformers. 13. typical is 30% network utilization. 14. assumes outputs are loaded, and all leds are used. symbol parameter description test conditions minimum maximum units v tsq rx 10base-t squelch threshold sinusoid 5 mhz am79c875 37 figure 11. mlt-3 and 10base-t test load with 1:1 transformer ratio figure 12. mlt-3 and 10base-t test load with 1.25:1 transformer ratio figure 13. near-end 100base-tx waveform tx+ tx- 0 . 01 f 75 5% 0 . 01 f ch a ss i s g r ou n d 100 2% ? 1:1 ? isol a t i o n t ran sfo r m er 49 . 9 49 . 9 v dd 22236g-13 tx+ tx- 0 . 01 f 75 5% 0 . 01 f ch a ss i s g r ou n d 100 2% ? 1:25:1 ? isol a t i o n t ran sfo r m er 78 . 1 78 . 1 v dd 22236g-14 112 n s v txout v txos tx + v txout - v txout 22236g-15 38 am79c875 figure 14. near-end 10base-t waveform figure 15. recommended pecl test loads v tx10ne 0 tx 10b a se-t 22236g-16 v dd = 5 v 82 . 5 130 p in v dd = 3 . 3 v 69 183 p in 5 v t e st lo a d 3 . 3 v t e st lo a d 22236g-17 am79c875 39 switching characteristics system clock signal notes: 1. parametric values are the same for commercial and industrial devices. figure 16. clock signal mlt-3 signals figure 17. mlt-3 test waveform symbol parameter description min. max. unit t clk refclk period 19.999 20.001 ns t clkh refclk width high 9 11 ns t clkl refclk width low 9 11 ns t clr refclk rise time - 5 ns t clf refclk fall time - 5 ns symbol parameter description min. max. unit t txr rise time of mlt-3 signal 3.0 5.0 ns t txf fall time of mlt-3 signal 3.0 5.0 ns t txrfs rise time and fall time symmetry of mlt-3 signal - 5 % t txdcd duty cycle distortion peak to peak - 0.5 ns t txj transmit jitter using scrambled idle signals - 1.4 ns t cl r 80% 20% t clf t clkh t clkl t clk tx_clk 22236g-18 t tx r t txf 16 n s tx t xtdcd t xtdcd 1 0 1 0 1 0 1 22236g-19 40 am79c875 mii management signals figure 18. management bus transmit timing figure 19. management bus receive timing symbol parameter description min. max. unit t mdper mdc period 40 ns t mdwh mdc pulse width high 16 ns t mdwl mdc pulse width low 16 ns t mdpd mdio delay from rising edge of mdc - 20 ns t mds mdio setup time to rising edge of mdc 4 ns t mdh mdio hold time from rising edge of mdc 3 ns mdc t md w h t md w l t mdpe r mdio t mdpd md i o_tx .v sd 22236g-20 mdc mdio t mds t mdh 22236g-21 am79c875 41 independent rmii mode signals 100 mbps rmii transmit figure 20. rmii 100 mbps transmit start of packet figure 21. rmii 100 mbps transmit end of packet timing symbol parameter description min. max. unit t rs100 tx_en[x], txd[x]_[1:0] setup time to refclk rising edge 4 - ns t rh100 tx_en[x], txd[x]_[1:0] hold time from refclk rising edge 2 - ns t rtj100 transmit latency tx_en[x] sampled by refclk to first bit of /j/ 60 100 ns t tidle100 required de-assertion time between packets 120 - ns r efclk t r s100 t r h100 t r s100 tx_en[x] txd[x]_[1:0] tx t r tj100 /j/ 22236g-22 r efclk tx_en[x] tx /j/ t tidle100 /t/ 22236g-23 42 am79c875 100 mbps rmii receive note: crs_dv[x] is asynchronous at the beginning of receiv e (1st rising edge of refclk), but is synchronous at the end of receive. figure 22. 100 mbps rmii receive start of packet timing figure 23. 100 mbps rmii receive end of packet timing symbol parameter description min. max. unit t rjc100 crs_dv[x] high after first bit of /j/ 80 150 ns t rcr100 rxd[x]_[1:0], crs_dv[x] delay after the rising edge of refclk 513ns t rtc100 first bit of /t/ to crs_dv[x] low 120 190 ns r x r efclk r xd[x]_[1:0] /j/ t r jc100 t r c r 100 c r s_d v [x] 22236g-24 r x r efclk r xd[x]_[1:0] /t/ r / t r tc100 c r s_d v [x] t r c r 100 t r c r 100 22236g-25 am79c875 43 10 mbps rmii transmit figure 24. rmii 10 mbps transmit start of packet figure 25. rmii 10 mbps transmit end of packet timing symbol parameter description min. max. unit t rs10 tx_en[x], txd[x]_[1:0] setup ti me to refclk rising edge 4 - ns t rh10 tx_en[x], txd[x]_[1:0] hold time from refclk rising edge 2 - ns t rtp10 transmit latency tx_en[x] sampled by refclk to start of packet 240 360 ns t tidle10 required de-assertion time between packets 300 - ns r efclk tx_en[x] txd[x]_[1:0] tx t r s10 t r tp10 t r s10 t r h10 22236g-26 tx r efclk tx_en[x] t tidle10 t r s10 22236g-27 44 am79c875 10 mbps rmii receive figure 26. 10 mbps rmii receive start of packet timing figure 27. 10 mbps rmii receive end of packet timing symbol parameter description min. max. unit t rspc10 crs_dv[x] high after start of packet 200 350 ns t rcr10 rxd[x]_[1:0], crs_d v[x] delay after the rising edge of refclk 513ns t repc10 end of packet to crs_dv[x] low 130 190 ns r x r efclk r xd[x]_[1:0] t r spc10 t r c r 10 c r s_d v [x] 22236g-28 r x r xd[x]_[1:0] t r epc10 c r s_d v [x] r efclk r c r 10 t r c r 10 t 22236g-29 am79c875 45 physical dimensions* pqr100 (measured in millimeters) *for reference only. bsc is an ansi standard for basic space centering. 14 . 00 0 . 10 20 . 00 0 . 10 1 30 80 81 100 51 23 . 20 0 . 25 0 . 3 0 . 1 0 . 65 3 . 40 0 . 25 2 . 70 0 . 2 1 . 60 0 . 12 0 . 88 0 . 2 17 . 20 0 . 25 46 am79c875 errata netphy? 4lp revision b.4 is the curren t production revision silicon with erra ta ? please refer to the descriptions below. revision b.4 errata summary the netphy? 4lp device has a total of 5 errata, all of wh ich are minor and should not cause concern. all informa- tion below should be used in conjunction with the netp hy? 4lp final datasheet pid 22236, available on the amd web site (www.amd.com). errata for netphy? 4lp b.4 the symptom section gives an external description of the problem. the implication section explains how the device behaves and its impact on the system. the wor karound section describes a workaround for the problem. the status section indicates when and how the prob lem will be fixed. b4.1) 10base-t signal acceptance compliance test suite - test #1411.11.03 symptom: crs response to signal 7a, 7b, 8a, 8b and 10 is unreliable unless the signal is preceded by a preamble. implication: these compliance tests reflect boundary conditions unlikely to happen in normal operation. some boundary conditions are meant to test the re ceiver's robustness and if it properly receives valid data. we have successfully received 10mbps data for all cable lengths, and we believe that the chance of failure in the field is extremely low. workaround: there is no external work around. status: this errata will not be fixed. b4.2) 10base-t local loopback symptom: 10base-t local loopback does not work. implication: this is a minor issue wh ich does not affect normal operation. workaround: loopback testing must be performed external to the device. status: this errata will not be fixed. b4.3) 10mb not interrupted by 100mb data reception symptom: if the phy is in 10base-t and for an unknown reason, 100mbps data is received, the phy should drop 10mb link and establish 100mb link. implication: this is a minor issue which should not affe ct normal operation. this is unh test 25.28c, where it is stated that the standard does not allow for this behavior and that no harm to the network is anticipated. additionally, it is not uncommon to find this issue with many phys today. workaround: there is no external workaround. status: this errata will not be fixed. b4.4) delayed idle following abnormal packet transmission symptom: if a packet does not end in a /t/r/, the rx_er signal does not go true immediately after, and is delayed 1 to 2 clock cycles. the re ceiver will then enter the idle state. implication: this is a mino r issue. if the packet does not termina te properly, rx_er is delayed 1-2 clock cycles. the issue is believed to be minor since the likelihood of encountering improperly termi- nated data packets is small. however, it will af fect the recording of er rors by the system. (unh 1.24) workaround: there is no external workaround. status: this errata will not be fixed. am79c875 47 b4.5) full duplex operation wi th auto-negotiation disabled symptom: if auto-negotiation is disa bled, the device cannot be pin-st rapped to full-duplex. leddpx[2]/ dplx (pin 41) should set the duplex at reset if ledact_link/anega (p in 39) is low at re- set. instead, all 4 ports are half-duplex regardless of the setting of pin 41. implication: this is a minor issue wh ich should not affect normal operat ion. auto-negotiation operation is usually set by default in systems today so that both link partners can operate at the highest set- ting (speed and duplex). very rarely do systems re ly on parallel detect to set the speed of the link. note that rmii operation is by definition, full-duplex. workaround: full-duplex operation must be set through management pins, register 0, bit 8. status: this errata will not be fixed. 48 am79c875 revision summary revision c to d 1. register 18, added bits 8 and 9 for user checking. 2. register 19, added bit 6, transformer ratio selection via software. 3. register 20, added bits 7:4, cable length indicators. 4. register 24, added bit 5, rx_er counter disable. 5. dc characteristics: added v oll , new i ih , i il and i oz maximum values 6. mii management signals: mdc period changed to 40ns (min), mdc pulse high/low changed to 16ns (min) 7. mii management signals: mdio delay changed to 20ns (max), mdio setup time changed to 4ns (min), mdio hold time changed to 3ns (max) revision d to e 1. specified using resistors in the range of 1 k to 4.7 k for setting the phyad pins. figure 8 reflects the correct resistors. 2. added bit 10, flow control support, to register 5. revision e to f 1. added industrial temperature support and new opn(ki). 2. minor edits. revision f to g 1. removed cim_dis references. 2. added pull-up resistor requirements fo r ledact_link[0] and leddpx[2]/dplx. 3. changed pull-up resistor values for leds to 1?4.7 k . 4. maximum input voltage is 5.5 v; operating voltage for 5-v-tolerant pins is 5.0 v. 5. minor edits. revision g to h 1. final version 2. corrected pull-up resistor value for ledact_link[2] to 1k?4.7k . 3. updated package drawing - some tolerances modified. revision h to i 1. edited temperature range information under ordering information on page 5. the contents of this document are provided in connection with adv anced micro devices, inc. (?amd?) products. amd makes no repre sentations or warranties with respect to the accuracy or completeness of the contents of this publication and reserves the right to make c hanges to speci- fications and product descriptions at any time without notice. no license, whether expre ss, implied, arising by estoppel or oth erwise, to any in- tellectual property rights is granted by this publication. except as set forth in am d's standard terms and conditions of sale, amd assumes no liability whatsoever, and discla ims any express or implied warranty, relating to its products including, but not limited to, th e implied warranty of merchantability, fitness for a part icular purpose, or infringement of any intellectual property right. amd's products are not designed, intended, authorized or warranted for use as components in systems intended for surgical impla nt into the body, or in other applications intended to support or sustain life , or in any other application in which the failure of amd's p roduct could create a situation where personal injury, death, or severe property or en vironmental damage may occur. amd reserves the right to discont inue or make changes to its products at any time without notice. trademarks copyright ? 2000, 2001, 2002, 2003, 2004, 2005 adv anced micro devices, inc. all rights reserved. amd, the amd logo, and combinations thereof are trademarks of advanced micro devices, inc. netphy is a trademark of advanced micro devices, inc. product names used in this publication are for identification purposes only and may be tr ademarks of their respective companies . |
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