serialcoder tm UR5HC703-600 extremely low-power keyboard encoder interfaces rs-232 serialcoder is a trademark of semtech corporation. all other trademarks belong to their respective companies. copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 1 hid & system management products, h/pc ic family description features 1 9 16 8 25 32 24 17 UR5HC703-600-fg lqfp c2 c1 c0 c14 c13 txd c12 r7 oscin _oscout vss c7 c8 c9 c10 c11 c3 c4 c5 c6 vdd2 _reset vss2 vdd c15 r0 r1 r2 r3 r4 r5 r6 ? 8 x 16 matrix encoding 9600 baud 8n1 serial data format ic is independent of the keyboard layout extremely low-power operation, transparent to the host average current consumption of less than 1 a at room temperature; 10 a at 85c customized versions available ttl/cmos output-only asynchronous serial interface to the host (direct connection to the uart) very simple serial protocol ? two- byte identification string on power- up; single-byte matrix-position for each key-press or key-release robust algorithm for ghost-key elimination the serialcoder tm UR5HC703 is an extremely low-power, ?off-the-shelf? serial keyboard encoder. robust, tiny and flexible, the ic is a good match for any application where the use of complicated keyboard protocols are not required and where asynchronous serial interface hardware is available. the serialcoder tm provides unprecedented power consumption minimization, making it ideal for use in add-on keyboards for handheld and cellular / web phones and single-board systems designed for portable applications. the ic provides extremely low-power operation, transparent to the host. power consumption is reduced to just the circuit?s leakage when all keys are released. the average current consumption is less than 1 a at room temperature and 10 a at 85c. if a single key or groups of keys are stuck in the depressed position, the ic will enter a total shutdown after a 10-minute wait ? to protect against unintended and unnecessary discharge of the batteries in the host. custom versions of the serialcoder tm are available with hardware handshaking for the communication channel, support for extra-low-power operations of the host, various baud rates and full- duplex i/o, etc. the serialcoder tm is simple to implement. it requires few external components and utilizes a tiny, low-profile 32-pin lqfp package that measures 7mm x 7mm. applications built-in keyboards for palm and h/pc devices add-on accessory keyboards for palm and h/pc devices portable personal computers instrumentation remote control cellular phones pin assignments
serialcoder tm functional diagram ordering code copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 2 txd 4 data buffer key matrix interface communication interface matrix scan logic reset logic oscillator power supply _reset oscin _oscout 8 16 r0-r7 c0-c15 package options pitch in mm ta = -20 c to +85 c 32-pin, plastic lqfp 0.8 UR5HC703-600-fg other materials type order number serialcoder tm eval. kit evaluation kit evk5-703-600-xxx
pin definitions copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 3 mnemonic pin # type name and function power supply vdd, vdd2 8,5 pwr positive supply voltage vss, vss2 11,7 pwr negative power supply : signal ground reset _reset 6 i hardware reset pin : reset input for orderly start-up. low logic level is required until power supply reaches minimum operating voltage oscillator pins osci 9 i oscillator input : connect ceramic resonator with built-in load capacitors or cmos clock from external oscillator 2 mhz operating frequency _osco 10 o oscillator output : connect ceramic resonator with built-in load capacitors or keep open if external oscillator is used host interface txd 27 0 serial data output : idle at high voltage (logical 1), non-inverted data (direct connection to the uart) scanned matrix pins row0-row7 18-25 i, pup row matrix inputs: with pulsed pull-up current sources col0-col15 1-4, o, nd column matrix output 12-17 26,28-32
protocol copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 4 serial transmissions are at the rate of 9600 baud, 8 data bits, no parity, least significant bit is transmitted first, idle/stop level is high (logical 1), start bit level is low (logical 0), non-inverted data. within 5ms after the power-up the ic sends a two-byte identification string of 0xf9, 0xfb. these two bytes are transmitted only once after each reset of the ic. these two id values also represent key release action in the locations [row=1, column=15] and [row=3, column=15] on the key matrix. since the values of these bytes represent release action of the keys, extraneous characters will never be generated, even if synchronization between the driver and ic is lost, or power fluctuations/erroneous resets are applied to the chip. if logistics of the driver do not permit "shared" use of the identification values 0xf9 and 0xfb, then the user is advised not to incorporate keys in the locations [row=1, column=15] and [row=3, column=15] for the key matrix design. subsequent single-byte transmissions indicate the row (0-7), column (0-15), and press/release action for each change of the state of every key. if after the current key release all of the keys on the key matrix are in the released state, the last transmission is repeated. host's driver looking for two bytes with exactly the same value and key release indication (b7=1) can recognize that the keyboard is completely idle. byte transmission bit number comment b7 0 for key press, 1 for key release b6 column location in the key matrix (0-15) b5 b4 b3 b2 row location in the key matrix (0-7) b1 b0
sample schematic for the UR5HC703-600-fg copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 5 rev 0.7 app circuit for UR5HC703-600-fg (c)1999-2000, usar systems - a semtech company to keyboard matrix c 3 1 c 4 2 c 5 3 c 6 4 v d d 2 5 r e s e t 6 v s s 2 7 v d d 8 oscin 9 oscout 10 vss 11 c7 12 c8 13 c9 14 c10 15 c11 16 c 1 5 1 7 r 0 1 8 r 1 1 9 r 2 2 0 r 3 2 1 r 4 2 2 r 5 2 3 r 6 2 4 r7 25 c12 26 txd 27 c13 28 c14 29 c0 30 c1 31 c2 32 u1 UR5HC703_600_fg 32-pin lqfp gnd ground power cmos_ttl_txd 9600 baud idle=high y1 2.00mhz c2 2.2uf 10v txd gnd gnd c1 .1uf gnd gnd gnd out 1 gnd 3 vdd 2 u2 voltage detector 2.2v or higher
serialcoder tm electrical characteristics copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 6 absolute maximum ratings ratings symbol value unit unit (vss = 0v, ambient temperature t a is in the range t low to t high ) supply voltage v dd -0.3 to +7.0 v input voltage: all input pins v in -0.3 to v dd +0.3 v output current: total peak for all pins i oh (peak) -80 i ol (peak) 80 ma total average for all pins i oh (avg) -40 i ol (avg) 40 ma peak for each pin i oh (peak) -10 i ol (peak) 10 ma average for each pin i oh (avg) -5 i ol (avg) 5 ma temperature range operating temperature t low to t high -20 to 85 c storage temperature t stg -40 to 125 c dc electrical characteristics, temperature range=t low to t high unless otherwise noted) characteristic symbol min typ max unit operating voltage v dd 2.2 5.5 v input voltage high v ih .8 v dd v dd v l ow v il 0 0.3 v dd v v il (_reset) 0 0.2 v dd v v il (oscin) 0 0.16 v dd v input current high l ih 5.0 a l ih (oscin) 4.0 a input current low i il -5.0 a i il (oscin) -4.0 a output voltage v oh i oh =-1.0ma v dd -1.0 v dd v v ol i ol =1.0ma 1.0 v power consumption i dd 600 a o ne or more keys are d epressed i dd a ll k eys are r eleased ta=25 c .1 1.0 a ta=85 c 10.0 a control timing (vdd=2.2 to 5.5 v, vss=0 vdc, temperature range=t low to t high unless otherwise noted) characteristic symbol value unit frequency of operations fosc ceramic resonator with built-in load 2.0 mhz capacitors external oscillator 2.0 mhz note: communications baud rate and active-state power consumption are scaled linearly with operating frequency. higher operating frequencies are possible within a reduced operating voltage range. consult semtech for further information.
mechanicals for the UR5HC703-600-fg lqfp package copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 7 a e f b y c a 1 a 2 l 1 l detail f e m d m e b 2 i 2 recommended pcb footprint ? 0.1 ? ?? 0.2 ? ? ?? ? ? ? ? ? symbol min nom max a a 2 b c d e h e l l 1 y b 2 dimension in millimeters h d a 1 0.5 ? ? i 2 1.0 ? ? m d 7.4 ? ? m e 7.4 10 ? 0 ? 0.1 1.0 0.7 0.5 0.3 9.2 9.0 8.8 9.2 9.0 8.8 0.8 7.1 7.0 6.9 7.1 7.0 6.9 0.175 0.125 0.105 0.45 0.35 0.3 1.4 0 1.7 e e h e 1 8 9 32 25 24 16 17 h d d
copyright ?1999-2001 semtech corporation doc5-703-600-ds-105 www.semtech.com 8 for sales information and product literature, contact: hid & system mgmt division semtech corporation 652 mitchell road newbury park, ca 91320 hidinfo@semtech.com http://www.semtech.com/ 805 498 2111 telephone 805 498 3804 telefax semtech western regional sales 805-498-2111 telephone 805-498-3804 telefax semtech central regional sales 972-437-0380 telephone 972-437-0381 telefax semtech eastern regional sales 203-964-1766 telephone 203-964-1755 telefax semtech asia-pacific sales office +886-2-2748-3380 telephone +886-2-2748-3390 telefax semtech japan sales office +81-45-948-5925 telephone +81-45-948-5930 telefax semtech korea sales sales +82-2-527-4377 telephone +82-2-527-4376 telefax northern european sales office +44 (0)2380-769008 telephone +44 (0)2380-768612 telefax southern european sales office +33 (0)1 69-28-22-00 telephone +33 (0)1 69-28-12-98 telefax central european sales office +49 (0)8161 140 123 telephone +49 (0)8161 140 124 telefax copyright ?1999-2001 semtech corporation. all rights reserved. serialcoder is a trademark of semtech corporation. semtech is a registered trademark of semtech corporation. all other trademarks belong to their respective companies. intellectual property disclaimer this specification is provided "as is" with no warranties whatsoever including any warranty of merchantability, fitness for any particular purpose, or any warranty otherwise arising out of any proposal, specification or sample. a license is hereby granted to reproduce and distribute this specification for internal use only. no other license, expressed or implied to any other intellectual property rights is granted or intended hereby. authors of this specification disclaim any liability, including liability for infringement of proprietary rights, relating to the implementation of information in this specification. authors of this specification also do not warrant or represent that such implementation(s) will not infringe such rights.
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