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tm 74act715, 74act715-r programmable video sync generator april 2007 ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 74act715, 74act715-r programmable video sync generator features maximum input clock frequency > 130mhz interlaced and non-interlaced formats available separate or composite horizontal and vertical sync and blank signals available complete control of pulse width via register programming all inputs are ttl compatible 8ma drive on all outputs default rs170/ntsc values mask programmed into registers act715-r is mask programmed to default to a clock enable state for easier start-up into 14.31818mhz rs170 timing general description the act715 and act715-r are 20-pin ttl-input compatible devices capable of generating horizontal, vertical and composite sync and blank signals for tele- visions and monitors. all pulse widths are completely definable by the user. the devices are capable of gener- ating signals for both interlaced and noninterlaced modes of operation. equalization and serration pulses can be introduced into the composite sync signal when needed. four additional signals can also be made available when composite sync or blank are used. these signals can be used to generate horizontal or vertical gating pulses, cursor position or vertical interrupt signal. these devices make no assumptions concerning the system architecture. line rate and field/frame rate are all a function of the values programmed into the data regis- ters, the status register, and the input clock frequency. the act715 is mask programmed to default to a clock disable state. bit 10 of the status register, register 0, defaults to a logic ?? this facilitates (re)programming before operation. the act715-r is the same as the act715 in all respects except that the act715-r is mask pro- grammed to default to a clock enabled state. bit 10 of the status register defaults to a logic ?? although completely (re)programmable, the act715-r version is better suited for applications using the default 14.31818mhz rs-170 register values. this feature allows power-up directly into operation, following a single clear pulse. ordering information device also available in tape and reel. specify by appending suffix letter ??to the ordering number. order number package number package description 74act715sc m20b 20-lead small outline integrated circuit (soic), jedec ms-013, 0.300" wide 74act715-rsc m20b 20-lead small outline integrated circuit (soic), jedec ms-013, 0.300" wide fact is a trademark of fairchild semiconductor corporation.
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 2 connection diagram pin description there are a total of 13 inputs and 5 outputs on the act715. data inputs d0?7: the data input pins connect to the address register and the data input register. addr /data: the addr /data signal is latched into the device on the falling edge of the load signal. the signal determines if an address (0) or data (1) is present on the data bus. l /hbyte: the l /hbyte signal is latched into the device on the falling edge of the load signal. the signal deter- mines if data will be read into the 8 lsb's (0) or the 4 msb's (1) of the data registers. a 1 on this pin when an addr/data is a 0 enables auto-load mode. load: the load control pin loads data into the address or data registers on the rising edge. addr / data and l /hbyte data is loaded into the device on the falling edge of the load. the load pin has been implemented as a schmitt trigger input for better noise immunity. clock: system clock input from which all timing is derived. the clock pin has been implemented as a schmitt trigger for better noise immunity. the clock and the load signal are asynchronous and indepen- dent. output state changes occur on the falling edge of clock. clr: the clear pin is an asynchronous input that ini- tializes the device when it is high. initialization consists of setting all registers to their mask programmed values, and initializing all counters, comparators and registers. the clear pin has been implemented as a schmitt trigger for better noise immunity. a clear pulse should be asserted by the user immediately after power-up to ensure proper initialization of the registers?ven if the user plans to (re)program the device. note: a clear pulse will disable the clock on the act715 and will enable the clock on the act715-r. odd/even : output that identifies if display is in odd (high) or even (low) field of interlace when device is in interlaced mode of operation. in noninterlaced mode of operation this output is always high. data can be seri- ally scanned out on this pin during scan mode. vcsync: outputs vertical or composite sync signal based on value of the status register. equalization and serration pulses will (if enabled) be output on the vcsync signal in composite mode only. vcblank: outputs vertical or composite blanking signal based on value of the status register. hblhdr: outputs horizontal blanking signal, horizon- tal gating signal or cursor position based on value of the status register. hsynvdr: outputs horizontal sync signal, vertical gating signal or vertical interrupt signal based on value of status register.
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 3 logic block diagram figure 1.
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 4 absolute maximum ratings stresses exceeding the absolute maximum ratings may damage the device. the device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. in addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. the absolute maximum ratings are stress ratings only. recommended operating conditions the recommended operating conditions table defines the conditions for actual device operation. recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. fairchild does not recommend exceeding them or designing to absolute maximum ratings. symbol parameter rating v cc supply voltage ?.5v to +7.0v i ik dc input diode current v i = ?.5v v i = v cc + 0.5v ?0ma +20ma v i dc input voltage ?.5v to v cc + 0.5v i ok dc output diode current v o = ?.5v v o = v cc + 0.5v ?0ma +20ma v o dc output voltage ?.5v to v cc + 0.5v i o dc output source or sink current ?5ma i cc or i gnd dc v cc or ground current per output pin ?0ma t stg storage temperature ?5? to +150? t j j unction temperature 140? symbol parameter rating v cc supply voltage 4.5v to 5.5v v i input voltage 0v to v cc v o output voltage 0v to v cc t a operating temperature ?0? to +85? ? v / ? t minimum input edge rate: v in from 0.8v to 2.0v, v cc @ 4.5v, 5.5v 125mv/ns
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 5 register description all of the data registers are 12 bits wide. width? of all pulses are defined by specifying the start count and end count of all pulses. horizontal pulses are specified with respect to the number of clock pulses per line and verti- cal pulses are specified with respect to the number of lines per frame. reg0?tatus register the status register controls the mode of operation, the signals that are output and the polarity of these outputs. the default value for the status register is 0 (000 hex) for the act715 and is ?024?(400 hex) for the act715-r. bits 0? bits 3? double equalization and serration mode will output equalization and serration pulses at twice the hsync frequency (i.e., 2 equalization or serration pulses for every hsync pulse). single equalization and serration mode will output an equalization or serration pulse for every hsync pulse. in interlaced mode equalization and serration pulses will be output during the vblank period of every odd and even field. interlaced single equalization and serration mode is not possible with this part. bits 5? bits 5 through 8 control the polarity of the outputs. a value of zero in these bit locations indicates an output pulse active low. a value of 1 indicates an active high pulse. b5 vcblank polarity b6?vcsync polarity b7?hblhdr polarity b8?hsynvdr polarity bits 9?1 bits 9 through 11 enable several different features of the device. b9 enable equalization/serration pulses (0) disable equalization/serration pulses (1) b10 disable system clock (0) enable system clock (1) default values for b10 are ??in the act715 and ??in the act715-r. b11 disable counter test mode (0) enable counter test mode (1) this bit is not intended for the user but is for internal testing only. horizontal interval registers the horizontal interval registers determine the number of clock cycles per line and the characteristics of the horizontal sync and blank pulses. reg1?horizontal front porch reg2 horizontal sync pulse end time reg3 horizontal blanking width reg4 horizontal interval width # of clocks per line ve r tical interval registers the vertical interval registers determine the number of lines per frame, and the characteristics of the vertical blank and sync pulses. reg5 vertical front porch reg6 vertical sync pulse end time reg7 vertical blanking width reg8 vertical interval width # of lines per frame equalization and serration pulse speci?ation registers these registers determine the width of equalization and serration pulses and the vertical interval over which they occur. reg 9 equalization pulse width end time reg10 serration pulse width end time reg11 equalization/serration pulse vertical interval start time reg12 equalization/serration pulse vertical interval end time ve r tical interrupt speci?ation registers these registers determine the width of the vertical interrupt signal if used. reg13 vertical interrupt activate time reg14 vertical interrupt deactivate time b 2 b 1 b 0 vcblank vcsync hblhdr hsynvdr 0 0 0 cblank csync hgate vgate (default) 0 0 1 vblank csync hblank vgate 0 1 0 cblank vsync hgate hsync 0 1 1 vblank vsync hblank hsync 1 0 0 cblank csync cusor vint 1 0 1 vblank csync hblank vint 1 1 0 cblank vsync cusor hsync 1 1 1 vblank vsync hblank hsync b 4 b 3 mode of operation 0 0 interlaced double serration and equalization (default) 0 1 non interlaced double serration 1 0 illegal state 1 1 non interlaced single serration and equalization
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 6 cursor location registers these 4 registers determine the cursor position location, or they generate separate horizontal and vertical gating signals. reg15 horizontal cursor position start time reg16 horizontal cursor position end time reg17 vertical cursor position start time reg18 vertical cursor position end time signal speci?ation horizontal sync and blank speci?ations all horizontal signals are defined by a start and end time. the start and end times are specified in number of clock cycles per line. the start of the horizontal line is consid- ered pulse 1 not 0. all values of the horizontal timing reg- isters are referenced to the falling edge of the horizontal blank signal ( see figure 2 ). since the first clock edge, clock #1, causes the first falling edge of the horizontal blank reference pulse, edges referenced to this first horizontal edge are n + 1 clocks away, where ??is the width of the timing in question. registers 1, 2, and 3 are programmed in this manner. the horizontal counters start at 1 and count until hmax. the value of hmax must be divisible by 2. this limitation is imposed because during interlace operation this value is internally divided by 2 in order to generate serration and equalization pulses at 2 the horizontal frequency. horizontal signals will change on the falling edge of the clock signal. signal specifications are shown below. horizontal period (hper) = reg(4) ckper horizontal blanking width = [reg(3) ?1] ckper horizontal sync width = [reg(2) ?reg(1)] ckper horizontal front porch = [reg(1) ?1] ckper ve r tical sync and blank speci?ations all vertical signals are defined in terms of number of lines per frame. this is true in both interlaced and nonin- terlaced modes of operation. care must be taken to not specify the vertical registers in terms of lines per field. since the first clock edge, clock #1, causes the first falling edge of the vertical blank (first horizontal blank) reference pulse, edges referenced to this first edge are n + 1 lines away, where ??is the width of the timing in question. registers 5, 6, and 7 are programmed in this manner. also, in the interlaced mode, vertical timing is based on half-lines. therefore registers 5, 6, and 7 must contain a value twice the total horizontal (odd and even) plus 1 (as described above). in non-interlaced mode, all vertical timing is based on whole-lines. register 8 is always based on whole-lines and does not add 1 for the first clock. the vertical counter starts at the value of 1 and counts until the value of vmax. no restrictions exist on the values placed in the vertical registers. vertical blank will change on the leading edge of hblank. verti- cal sync will change on the leading edge of hsync. (see figure 3.) vertical frame period (vper) = reg(8) hper vertical field period (vper/n) = reg(8) hper/n vertical blanking width = [reg(7) ?1] hper/n vertical syncing width = [reg(6) ?reg(5)] hper/n vertical front porch = [reg(5) ?1] hper/n where, n = 1 for noninterlaced n = 2 for interlaced composite sync and blank speci?ations composite sync and blank signals are created by logi- cally anding (oring) the active low (high) signals of the corresponding vertical and horizontal components of these signals. the composite sync signal may also include serration and/or equalization pulses. the serra- tion pulse interval occurs in place of the vertical sync interval. equalization pulses occur preceding and/or following the serration pulses. the width and location of these pulses can be programmed through the registers shown below. (see figure 4.) horizontal equalization pw = [reg(9) ?reg(1)] ckper reg 9 = (hfp) + (heqp) + 1 horizontal serration pw = [reg(4)/n + reg(1) ?reg(10)] ckper reg 10 = (hfp) + (hper/2) ?(hserr) + 1 where, n = 1 for noninterlaced single serration/equalization n = 2 for noninterlaced double serration/equalization n = 2 for interlaced operation
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 7 figure 2. horizontal wave speci?ation figure 3. vertical waveform speci?ation figure 4. equalization/serration interval programming
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 8 horizontal and vertical gating signals horizontal drive and vertical drive outputs can be uti- lized as general purpose gating signals. horizontal and vertical gating signals are available for use when com- posite sync and blank signals are selected and the value of bit 2 of the status register is 0. the vertical gating signal will change in the same manner as that specified for the vertical blank. horizontal gating signal width = [reg(16) ?reg(15)] ckper vertical gating signal width = [reg(18) ?reg(17)] hper cursor position and vertical interrupt the cursor position and vertical interrupt signal are available when composite sync and blank signals are selected and bit 2 of the status register is set to the value of 1. the cursor position generates a single pulse of n clocks wide during every line that the cursor is spec- ified. the signals are generated by logically oring (anding) the active low (high) signals specified by the registers used for generating horizontal and vertical gating signals. the vertical interrupt signal generates a pulse during the vertical interval specified. the vertical interrupt signal will change in the same manner as that specified for the vertical blanking signal. horizontal cursor width = [reg(16) ?reg(15)] ckper vertical cursor width = [reg(18) ?reg(17)] hper vertical interrupt width = [reg(14) ?reg(13)] hper addressing logic the register addressing logic is composed of two blocks of logic. the first is the address register and counter (addrcntr), and the second is the address decode (addrdec). addrcntr logic addresses for the data registers can be generated by one of two methods. manual addressing requires that each byte of each register that needs to be loaded needs to be addressed. to load both bytes of all 19 registers would require a total of 57 load cycles (19 address and 38 data cycles). auto addressing requires that only the initial register value be specified. the auto load sequence would require only 39 load cycles to com- pletely program all registers (1 address and 38 data cycles). in the auto load sequence the low order byte of the data register will be written first followed by the high order byte on the next load cycle. at the time the high byte is written the address counter is incremented by 1. the counter has been implemented to loop on the initial value loaded into the address register. for example: if a value of 0 was written into the address register then the counter would count from 0 to 18 before resetting back to 0. if a value of 15 was written into the address register then the counter would count from 15 to 18 before loop- ing back to 15. if a value greater than or equal to 18 is placed into the address register the counter will continu- ously loop on this value. auto addressing is initiated on the falling edge of load when addrdata is 0 and lhbyte is 1. incrementing and loading of data registers will not commence until the falling edge of load after addrdata goes to 1. the next rising edge of load will load the first byte of data. auto incrementing is dis- abled on the falling edge of load after addrdata and lhbyte goes low.
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 9 manual addressing mode auto addressing mode cycle # load falling edge load rising edge 1 enable manual addressing load address m 2 enable lbyte data load load lbyte m 3 enable hbyte data load load hbyte m 4 enable manual addressing load address n 5 enable lbyte data load load lbyte n 6 enable hbyte data load load hbyte n cycle # load falling edge load rising edge 1 enable auto addressing load start address n 2 enable lbyte data load load lbyte (n) 3 enable hbyte data load load hbyte (n); inc counter 4 enable lbyte data load load lbyte (n+1) 5 enable hbyte data load load hbyte (n+1); inc counter 6 enable manual addressing load address
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 10 addrdec logic the addrdec logic decodes the current address and generates the enable signal for the appropriate register. the enable values for the registers and counters change on the falling edge of load. two types of addrdec logic is enabled by 2 pair of addresses, addresses 22 or 54 (vectored restart logic) and addresses 23 or 55 (vectored clear logic). loading these addresses will enable the appropriate logic and put the part into either a restart (all counter registers are reinitialized with prepro- grammed data) or clear (all registers are cleared to zero) state. reloading the same addrdec address will not cause any change in the state of the part. the outputs during these states are frozen and the internal clock is disabled. clocking the part during a vectored restart or vectored clear state will have no effect on the part. to resume operation in the new state, or disable the vectored restart or vectored clear state, another non-addrdec address must be loaded. operation will begin in the new state on the rising edge of the non- addrdec load pulse. it is recommended that an unused address be loaded following an addrdec oper- ation to prevent data registers from accidentally being corrupted. the following addresses are used by the device. address 0 status register reg0 address 1?8 data registers reg1?eg18 address 19?1 unused address 22/54 restart vector (restarts device) address 23/55 clear vector (zeros all registers) address 24?1 unused address 32?0 register scan addresses address 51?3 counter scan addresses address 56?3 unused at any given time only one register at most is selected. it is possible to have no registers selected. v ectored restart address the function of addresses 22 (16h) or 54 (36h) are sim- ilar to that of the clr pin except that the preprogram- ming of the registers is not affected. it is recommended but not required that this address is read after the initial device configuration load sequence. a 1 on the addrdata pin (auto addressing mode) will not cause this address to automatically increment. the address will loop back onto itself regardless of the state of addrdata unless the address on the data inputs has been changed with addrdata at 0. v ectored clear address addresses 23 (17h) or 55 (37h) is used to clear all regis- ters to zero simultaneously. this function may be desir- able to use prior to loading new data into the data or status registers. this address is read into the device in a similar fashion as all of the other registers. a 1 on the addrdata pin (auto addressing mode) will not cause this address to automatically increment. the address will loop back onto itself regardless of the state of addrdata unless the address on the data inputs has been changed with addrdata at 0. figure 5. addrdec timing gen locking the act715 and act715-r is designed for master sync and blank signal generation. however, the devices can be synchronized (slaved) to an external tim- ing signal in a limited sense. using vectored restart, the user can reset the counting sequence to a given loca- tion, the beginning, at a given time, the rising edge of the load that removes vector restart. at this time the next clock pulse will be clock 1 and the count will restart at the beginning of the first odd line. preconditioning the part during normal operation, before the desired synchronizing pulse, is necessary. however, since load and clock are asynchronous and inde- pendent, this is possible without interruption or data and performance corruption. if the defaulted 14.31818mhz rs-170 values are being used, preconditioning and restarting can be minimized by using the clear pulse instead of the vectored restart operation. the act715-r is better suited for this application because it eliminates the need to program a 1 into bit 10 of the status register to enable the clock. gen locking to another count location other than the very beginning or separate horizontal/vertical resetting is not possible with the act715 nor the act715-r. scan mode logic a scan mode is available in the act715 that allows the user to non-destructively verify the contents of the regis- ters. scan mode is invoked through reading a scan address into the address register. the scan address of a given register is defined by the data register address + 32. the internal clocking signal is disabled when a scan address is read. disabling the clock freezes the device in it's present state. data can then be serially scanned out of the data registers through the odd/even pin. the lsb will be scanned out first. since each register is 12 bits wide, completely scanning out data of the addressed register will require 12 clock pulses. more
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 11 than 12 clock pulses on the same register will only cause the msb to repeat on the output. re-scanning the same register will require that register to be reloaded. the value of the two horizontal counters and 1 vertical counter can also be scanned out by using address num- bers 51?3. note that before the part will scan out the data, the load signal must be brought back high. normal device operation can be resumed by loading in a non-scan address. as the scanning of the registers is a non-destructive scan, the device will resume correct operation from the point at which it was halted. rs170 default register values the tables below show the values programmed for the rs170 format (using a 14.31818 mhz clock signal) and how they compare against the actual eia rs170 specifi- cations. the default signals that will be output are csync, cblank, hdrive and vdrive. the device initially starts at the beginning of the odd field of inter- lace. all signals have active low pulses and the clock is disabled at power up. registers 13 and 14 are not involved in the actual signal information. if the vertical interrupt was selected so that a pulse indicating the active lines would be output. reg d value h register description reg0 0 000 status register (715) reg0 1024 400 status register (715-r) reg1 23 017 hfp end time reg2 91 05b hsync pulse end time reg3 157 09d hblank pulse end time reg4 910 38e total horizontal clocks reg5 7 007 vfp end time reg6 13 00d vsync pulse end time reg7 41 029 vblank pulse end time reg8 525 20d total vertical lines reg9 57 039 equalization pulse end time reg10 410 19a serration pulse start time reg11 1 001 pulse interval start time reg12 19 013 pulse interval end time reg13 41 029 vertical interrupt activate time reg14 526 20e vertical interrupt deactivate time reg15 911 38f horizontal drive start time reg16 92 05c horizontal drive end time reg17 1 001 vertical drive start time reg18 21 015 vertical drive end time rate period input clock 14.31818mhz 69.841ns line rate 15.73426khz 63.556? field rate 59.94hz 16.683ms frame rate 29.97hz 33.367ms
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 12 rs170 horizontal data rs170 verticle data signal width ? %h speci?ation (?) hfp 22 clocks 1.536 1.5 ?0.1 hsync width 68 clocks 4.749 7.47 4.7 ?0.1 hblank width 156 clocks 10.895 17.15 10.9 ?0.2 hdrive width 91 clocks 6.356 10.00 0.1h ?0.005h heqp width 34 clocks 2.375 3.74 2.3 ?0.1 hserr width 68 clocks 4.749 7.47 4.7 ?0.1 hper iod 910 clocks 63.556 100 signal width ? %h speci?ation (?) vfp 3 lines 190.67 6 eqp pulses vsync width 3 lines 190.67 6 serration pulses vblank width 20 lines 1271.12 7.62 0.075v ?0.005v vdrive width 11.0 lines 699.12 4.20 0.04v ?0.006v veqp intrvl 9 lines 3.63 9 lines/field vperiod (?ld) 262.5 lines 16.683 ms 16.683ms/field vperiod (frame) 525 lines 33.367 ms 33.367ms/frame
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 13 dc electrical characteristics for act family devices over operating temperature range (unless otherwise specified). notes: 1. all outputs loaded; thresholds on input associated with input under test. 2. test load 50pf, 500 ? to ground. ac electrical characteristics symbol p arameter v cc (v) conditions t a = +25?, c l = 50pf t a = ?0? to +85? units t yp. guaranteed limits v ih minimum high level input voltage 4.5 v out = 0.1v or v cc ?0.1v 1.5 2.0 2.0 v 5.5 1.5 2.0 2.0 v il maximum low level input voltage 4.5 v out = 0.1v or v cc ?0.1v 1.5 0.8 0.8 v 5.5 1.5 0.8 0.8 v oh minimum high level output voltage 4.5 i out = ?0 ? 4.49 4.4 4.4 v 5.5 5.49 5.4 5.4 4.5 v in = v il /v ih , i oh = ? ma (1) 3.86 3.76 v 5.5 4.86 4.76 v ol maximum low level output voltage 4.5 i out = 50? 0.001 0.1 0.1 v 5.5 0.001 0.1 0.1 4.5 v in = v il /v ih , i oh = +8ma (1) 0.36 0.44 v 5.5 0.36 0.44 i old minimum dynamic output current 5.5 v old = 1.65v 32.0 ma i ohd minimum dynamic output current 5.5 v ohd = 3.85v ?2.0 ma i in maximum input leakage current 5.5 v i = v cc , gnd ?.1 ?.0 ? i cc supply current quiescent 5.5 v in = v cc , gnd 8.0 80 ? i cct maximum i cc /input 5.5 v in = v cc ?2.1v 0.6 1.5 ma symbol p arameter v cc (v) t a = +25?, c l = 50pf t a = ?0? to +85?, c l = 50pf units min. typ. max. min. max. f maxi interlaced f max (hmax/2 is odd) 5.0 170 190 150 mhz f max non-interlaced f max (hmax/2 is even) 5.0 190 220 175 mhz t plh1 , t phl1 clock to any output 5.0 4.0 13.0 15.5 3.5 18.5 ns t plh2 , t phl2 clock to oddeven (scan mode) 5.0 4.5 15.0 17.0 3.5 20.5 ns t plh3 load to outputs 5.0 4.0 11.5 16.0 3.0 19.5 ns
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 14 ac operating requirements note: 3. removal of vectored reset or restart to clock. capacitance figure 6. ac speci?ations symbol p arameter v cc (v) t a = +25? t a = ?0? to +85? units t yp. guaranteed minimums control setup time: 5.0 t sc addr/data to load 3.0 4.0 4.5 ns t sc l/hbyte to load 3.0 4.0 4.5 ns t sd data setup time: d7?0 to load+ 5.0 2.0 4.0 4.5 ns control hold time: 5.0 t hc load?to addr/data 0 1.0 1.0 ns t hc load?to l/hbyte 0 1.0 1.0 ns t hd data hold time: load+ to d7?0 5.0 1.0 2.0 2.0 ns t rec load+ to clk (3) 5.0 5.5 7.0 8.0 ns load pulse width: 5.0 t wld low 3.0 5.5 5.5 ns t wld+ high 3.0 5.0 7.5 ns t wclr clr pulse width high 5.0 5.5 6.5 9.5 ns t wck clock pulse width (high or low) 5.0 2.5 3.0 3.5 ns symbol parameter conditions typ. units c in input capacitance v cc = 5.0v 7.0 pf c pd power dissipation capacitance v cc = 5.0v 17.0 pf
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 15 additional applications information po wering up the act715 default value for bit 10 of the status regis- ter is 0. this means that when the clear pulse is applied and the registers are initialized by loading the default values the clock is disabled. before operation can begin, bit 10 must be changed to a 1 to enable clock. if the default values are needed (no other pro- gramming is required) then figure 7 illustrates a hard- wired solution to facilitate the enabling of the clock after power-up. should control signals be difficult to obtain, figure 8 illustrates a possible solution to auto- matically enable the clock upon power-up. use of the act715-r eliminates the need for most of this circuitry. modifications of the figure 8 circuit can be made to obtain the lone clear pulse still needed upon power-up. note that, although during a vectored restart none of the preprogrammed registers are affected, some signals are affected for the duration of one frame only. these signals are the horizontal and vertical drive signals. after a vectored restart the beginning of these signals will occur at the first clk. the end of the signals will occur as programmed. at the completion of the first frame, the signals will resume to their programmed start and end time. preprogramming ?n-the-fly although the act715 and act715-r are completely programmable, certain limitations must be set as to when and how the parts can be reprogrammed. care must be taken when reprogramming any end time reg- isters to a new value that is lower than the current value. should the reprogramming occur when the counters are at a count after the new value but before the old value, then the counters will continue to count up to 4096 before rolling over. for this reason one of the following two precautions are recommended when reprogramming ?n-the-fly? the first recommendation is to reprogram horizontal values during the horizontal blank interval only and/or vertical values during the vertical blank interval only. since this would require delicate timing requirements the second recommendation may be more appropriate. the second recommendation is to program a vectored restart as the final step of reprogramming. this will ensure that all registers are set to the newly pro- grammed values and that all counters restart at the first clk position. this will avoid overrunning the counter end times and will maintain the video integrity. figure 7. default rs170 hardwire con?uration
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 16 note: a 74hc221a may be substituted for the 74hc423a pin 6 and pin 14 must be hardwired to gnd components r1: 4.7k c1: 10? r2: 10k c2: 50pf figure 8. circuit for clear and load pulse generation
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 17 physical dimensions dimensions are in inches (millimeters) unless otherwise noted. figure 9. 20-lead small outline integrated circuit (soic), jedec ms-013, 0.300" wide pa ck ag e number m20b
74act715, 74act715-r programmable video sync generator ?988 fairchild semiconductor corporation www.fairchildsemi.com 74act715, 74act715-r rev. 1.3 18 tradem a rks the following are registered and unregistered trademarks fairchild semiconductor owns or is authorized to use and is not intend ed to be an exhaustive list of all such trademarks. acex across the board. around the world. activearray bottomless build it now coolfet crossvolt ctl current transfer logic dome e 2 cmos ecospark ensigna fact quiet series fact fast fastr fps frfet globaloptoisolator gto hisec i-lo implieddisconnect intellimax isoplanar microcoupler micropak microwire msx msxpro ocx ocxpro optologic optoplanar pacman pop power220 power247 poweredge powersaver powertrench programmable active droop qfet qs qt optoelectronics quiet series rapidconfigure rapidconnect scalarpump smart start spm stealth superfet supersot -3 supersot -6 supersot -8 syncfet tcm the power franchise tinyboost tinybuck tinylogic tinyopto tinypower tinywire trutranslation p serdes uhc unifet vcx wire disclaimer fairchild semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. fairchild does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others. these specifications do not expand the terms of fairchild? worldwide terms and conditions, specifically the warranty therein, which covers these products. life support policy fairchild? products are not authorized for use as critical components in life support devices or systems without the express written approval of fairchild semiconductor corporation. as used herein: 1. life support devices or systems are devices or systems wh ich, (a) are intended for surgical implant into the body or (b) support or sustain life, and (c) whose failure to perform w hen properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. a critical component in any component of a life support, device, or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. product status definitions definition of terms datasheet identification product status definition advance information formative or in design this datasheet contains the design specifications for product development. specifications may change in any manner without notice. preliminary first production this datasheet contains preliminary data; supplementary data will be published at a later date. fairchild semiconductor reserves the right to make changes at any time without notice to improve design. no identification needed full production this datasheet contains final specifications. fairchild semiconductor reserves the right to make changes at any time without notice to improve design. obsolete not in production this datasheet contains specifications on a product that has been discontinued by fairchild semiconductor. the datasheet is printed for reference information only. re v. i24

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