serialcoder? 700 UR5HC703-700 extremely low-power keyboard encoder interfaces rs-232 serialcoder, keycoder, and self-power management are trademarks of semtech corporation. all other trademarks belong to their respective companies. copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 1 hid & system management products, keycoder? family description features 1 8 9 32 25 24 16 17 col3 col4 col5 col6 vdd2 reset vss2 vdd row6 row5 row4 row3 row2 row1 row0 rxd ocsin oscout vss col7 col8 col9 col10 col11 row7 col12 txd col13 hs col0 col1 col2 UR5HC703-700-fg lqfp ? 8 x 14 keyboard matrix encoding ic is independent of the keyboard layout extremely low-power operation, transparent to the host typical current consumption of less than 1 a at room temperature; 10 a at 85c 9600 baud 8n1 serial data format direct connection to rs-232 signals from the host uart simple, proprietary serial protocol robust algorithm for ghost-key elimination self-power management?, sleeps between keystrokes the serialcoder? 700 UR5HC703-700 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? 700 provides self-power management? and draws its power entirely from the host device. it is ideal for use in add-on keyboards for handheld and cellular / web phones and other portable applications. self-power management? is 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 key or group of keys stays in the depressed position for ten minutes (with no other keyboard activity), the ic shuts down to save power. the serialcoder? 700 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 personal digital assistant (pda) and hand- held pc (h/pc) devices add-on accessory keyboards for pda and h/pc devices portable personal computers instrumentation remote control cellular phones pin assignments preliminary
serialcoder? 700 functional diagram ordering code copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 2 4 data buffer key matrix interface communication interface matrix scan logic reset logic oscillator power supply _reset oscin _oscout 8 14 r0-r7 c0-c13 UR5HC703-700 txd rxd hs package options pitch ta = -20 c to +85 c 32-pin, plastic lqfp 0.8 mm UR5HC703-700-fg other materials type order number serialcoder? 700 eval. kit evaluation kit evk5-703-700
pin definitions copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 3 mnemonic pin # type name and function power supply v dd , v dd 2 8, 5 pwr positive supply voltage v ss , v ss 2 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 whenever v dd is below minimum operating voltage oscillator pins oscin 9 i oscillator input : connect ceramic resonator with built-in load capacitors; 2 mhz operating frequency _oscout 10 o oscillator output : connect ceramic resonator with built-in load capacitors host interface txd 27 o serial data output : idle at 0v, non-inverted data (direct connection to rs232 port) rxd 17 i serial data input hs 29 o ? hot? synchronization signal scanned matrix pins row0-row7 18-25 i row matrix inputs with pulsed pull-up current sources col0-col13 30-32, o column matrix output , open drain 1-4, 12-16, 26, 28 note: an underscore before a pin mnemonic denotes an active low signal. protocol the serialcoder? 700 uses a proprietary serial protocol (patent pending) for two-way communication with the host device. the specification for this protocol is available, subject to a non-disclosure agreement (nda), to customers and driver developers. this protocol allows the host device to save significant power, by indicating to the host device when it can lower its power consumption to a minimum. this flexible protocol can also accommodate additional types of data if desired; for example, position data from a pointing stick embedded in the keyboard.
?ghost? keys keyboard scanner copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 4 in any scanned contact switch matrix, whenever three keys defining a rectangle on the switch matrix are pressed at the same time, a fourth key positioned on the fourth corner of the rectangle is sensed as being pressed. this is known as the ?ghost? or ?phantom? key problem. figure 1 : ?ghost? or ?phantom? key problem although the problem cannot be totally eliminated without using external hardware, there are methods to neutralize its negative effects for most practical applications. keys that are intended to be used in combinations should be placed in the same row or column of the matrix, whenever possible. shift keys (shift, alt, ctrl, window) should not reside in the same row (or column) as any other keys. the serialcoder? has built-in mechanisms to detect the presence of ?ghost? keys. actual key presses ?ghost? key the encoder scans a keyboard organized as an 8 row by 14 column matrix for a maximum of 112 keys. smaller size matrixes can also be accommodated by simply leaving unused pins open. the serialcoder? provides internal pull-ups for the row input pins. when active, the encoder selects one of the column lines (c0-c13) every 512 s and then reads the row data lines (r0-r7). a key closure is detected as a zero in the corresponding position of the matrix. a complete scan cycle for the entire keyboard takes approximately 9.2 ms. each key found pressed is debounced for a period of 20 ms. once the key is verified, the corresponding key code(s) are loaded into the transmit buffer of the serial communication channel. n-key rollover means the code(s) corresponding to each key press are transmitted to the host system as soon as that key is debounced, indepen- dent of the release of other keys. when a key is released, the corresponding break code is transmitted to the host system. several keys can be held pressed at the same time. however, if two or more key closures occur within a time interval of less than 5 ms, an error flag is set, and those closures are not processed. this feature protects against the effects of accidental key presses. the serialcoder? 700 achieves uniquely low system power consumption, due partly to self-power management?, and partly to the proprietary protocol the ic uses to communicate with the the host system driver. self- power management? powers down the ic between key presses; a key press wakes up the ic immediately without losing any key data. the protocol allows the host system to power down the power-wasting charge pumps (for the communications interface) after a short period of inactivity. alerting the host on connection when a keyboard assembly (including the serialcoder? 700 and the recommended components) is plugged into a host system, the serialcoder? 700 sends an identification code to the host, and forces the host into a state where the host can acknowledge the code. after the host receives and acknowledges this code, the host is aware that the keyboard assembly is connected, and the host can then choose what to do next. for example, (1) the host can choose to enter a fully awakened state, and turn on the screen, etc. (2) if no keys have been pressed, the host can choose to return to a sleep state. n-key rollover power management
evaluation board note copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 5 note: jumper setting when using the serialcoder? 700 evaluation board, and powering the ic from the pda interface, jumper 3 (j3) must be open; when powering from the rs232 port, jumper 3 must be closed.
sample schematic for the serialcoder? 700 UR5HC703-700-fg copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 6 partial bom y1 = pbrc-2.00 br (avx), cstc2.00mg (murata) u2 = mn1382e (panasonic), tc54vc2402ecb (microchip) txd 9600 baud idle=low 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 r x d 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 hs 29 c0 30 c1 31 c2 32 u1 ur5hc703_700_fg 32-pin lqfp gnd r1 100k w r2 100k w to pda's 10-pin connector. 1 2 3 4 5 6 7 8 9 10 jp1 vdd rxd txd hs r3 47 w y1 2.00mhz gnd gnd c2 1.0f 10v r4 47 w c1 0.1f gnd gnd gnd out 1 gnd 3 vdd 2 u2 voltage detector 2.2v or higher gnd
serialcoder? 700 electrical characteristics copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 7 absolute maximum ratings ratings symbol value 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 esd rating (human body model) v esd 2.0 kv 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 0.8 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 i oh =-1.0ma v oh v dd -1.0 v dd v i ol =1.0ma v ol 0 1.0 v power consumption o ne or more keys are depressed i dd 1.5 ma a ll keys are released ta=25c i dd 0.1 1.0 a ta=85c i dd 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 operation ceramic resonator with built-in load capacitors fosc 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 serialcoder? 700 UR5HC703-700-fg lqfp package copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 8 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 doc5-703-700-ds-105 www.semtech.com 9 this page left intentionally blank
copyright ?1999-2001 semtech corporation doc5-703-700-ds-105 www.semtech.com 10 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, keycoder, and self-power management are trademarks 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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