turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 1 of 7 KBDP64 ic parallel output keyboard e ncoder for up to 64 keys general description the KBDP64 ic is designed to provide a parallel binary outpu t encoder for keyboards up to 64 keys. the KBDP64 ic contains all the logic necessary to encode a spst keyboard switch array up to 8 by 8 in size and provide a parallel binary output and a data available strobe . the data available strobe goes high when a key is pressed, and goes low when the key is released. the data outputs keep their states after the key is rele ased. the array can be a 8 x 8 array, but any smaller size may be used. the KBDP64 handles debouncing and encodes the keys with no external parts. all timing is internally generated. no external diodes are required in the array to prevent key ghosting in a two key rollover situation. a .1 uf bypass capacitor is sug gested across the vdd and vss pins. the part uses the standard 28 pin .3 inch width soic package. features parallel data output plus data available strobe . fully encodes a key switch arra y . (up to 8 x 8 ) no external parts required . low power consumption 2 ma typical. last key pressed retained on outputs supply voltage 2.4 to 5 .25 volts . all timing internally generated . 2 key rollover . on chip row input resistors . internal key bounce elimin ation . ttl and cmos compatible outputs . part is in full production . soic 28 pin package . low emi rohs compliant
turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 2 of 7 example circuit data out e KBDP64 15 9 16 17 18 19 5 6 7 8 10 11 13 14 22 12 20 23 28 21 24 4 25 3 26 2 27 1 colx1 nc colx3 colx5 colx7 nc rowy8 rowy6 rowy4 rowy2 colx8 colx6 colx2 vss rowy5 colx4 rowy1 rowy7 vdd rowy3 douta doutb doutc doutd doute doutf nc dataavail data out f data out a data out b 00 01 02 08 09 0a 10 11 12 18 19 1a 03 04 05 06 07 0b 0c 0d 0e 0f 13 14 15 16 17 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f keypad c1 c2 c3 c4 c5 c6 c7 r8 r7 r6 r1 r2 r3 r4 r5 c8 data out c data avilable data out d vcc
turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 3 of 7 connection diagram KBDP64 15 9 16 17 18 19 5 6 7 8 10 11 13 14 22 12 20 23 28 21 24 4 25 3 26 2 27 1 colx1 nc colx3 colx5 colx7 nc rowy8 rowy6 rowy4 rowy2 colx8 colx6 colx2 vss rowy5 colx4 rowy1 rowy7 vdd rowy3 douta doutb doutc doutd doute doutf nc dataavail pin description pin # description pin # description 1 data avai l 28 vdd 2 d out f (msb) 27 n c 3 d out d 26 d out e 4 d out b 25 d out c 5 row y 8 24 d out a (lsb) 6 row y 6 23 row y7 7 row y 4 22 row y5 8 row y 2 21 row y3 9 nc 20 row y1 10 col x8 19 nc 11 col x6 18 col x7 12 col x4 17 col x5 13 col x 2 16 col x 3 14 vss 15 col x 1 col x1 ? col x8 these pins are open drain column driver outputs to the key matrix . row y1 ? row y8 these pins are the row inputs from the key matrix . these inputs have 5.6k (nominal) pull up resistor s on chip. d out a - doutf th ese are t he parallel data outputs. d ou t a is the least significant bit. these bits form a binary code for the pressed key. these outputs keep their state even after the key is released. data avail this pin goes high when a key is pressed, and low when the key is released. in the case of a 2 key rollover, the pin goes low before the dout bits change, then goes high again. vss connect to system ground.
turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 4 of 7 vdd connect to supply voltage of 2.4 to 5 volts . a .1 uf decoupling capacitor to ground is recommended. notes: make n o connection to the nc pins . pin s 9 and 19 must be left unconnected . truth table t he output codes of the kbd64 start at zero, and progress upwards in a binary count . the hex output of the dout bits is shown in the right column. custom output codes are available, consult t he factory for information. rowy 1 rowy 2 rowy 3 rowy 4 rowy 5 rowy 6 rowy 7 rowy 8 hex colx1 x 00 colx1 x 01 colx1 x 02 colx1 x 03 colx1 x 04 colx1 x 05 colx1 x 06 colx1 x 07 colx2 x 08 co lx2 x 09 colx2 x 0a colx2 x 0b colx2 x 0c colx2 x 0d colx2 x 0e colx2 x 0f colx3 x 10 colx3 x 11 colx3 x 12 colx3 x 13 colx3 x 14 colx3 x 15 colx3 x 16 colx3 x 17 colx4 x 18 colx4 x 19 colx4 x 1a colx4 x 1b colx4 x 1c colx4 x 1d colx4 x 1e colx4 x 1f colx5 x 20 colx5 x 21 colx5 x 22 colx5 x 23 c olx5 x 24
turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 5 of 7 colx5 x 25 colx5 x 26 colx5 x 27 colx6 x 28 colx6 x 29 colx6 x 2a colx6 x 2b colx6 x 2c colx6 x 2d colx6 x 2e colx6 x 2f colx7 x 30 colx7 x 31 colx7 x 32 colx7 x 33 colx7 x 34 colx7 x 35 colx7 x 36 colx7 x 37 colx8 x 38 colx8 x 39 colx8 x 3a colx8 x 3b colx8 x 3c colx8 x 3d colx8 x 3e colx8 x 3f absolute maximum ratings symbol description min typical max units notes t stg storage t emperature - 55 25 + 100 oc t a operating temperature - 40 +85 oc v dd v dd - v ss voltage - 0 .5 +6.0 v v io input voltage v ss - 0 .5 v dd + 0 . 5 v i mio maximum current into any pin - 25 +50 ma esd electrostatic discharge voltage 2000 v human body model esd lu latch up current 200 ma
turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 6 of 7 dc electrical characteristics symbol description min typical max units notes v dd s upply voltage 2.4 5.25 v i dd supply current 2 8 ma v dd = 5v v oh high output level v dd - 1.0 v i oh =10 ma v ol low output voltage 0.75 v i ol =25 ma v ih input high level 2.1 v v il input low level 0.8 v i oh high level source current 10 ma i ol low leve l sink current 25 ma c io capacitive load 3.5 10 pf i il input leakage 1 na r pu pull up resistors on row inputs 4 5.6 8 k ? theory of operation the KBDP64 ic is a custom programmed microprocessor designed to encod e keyboards and provide a parallel output. the open drain col x pins are pulsed low one at a time, and the row y pins are sampled to check for key switch closur es. if a key is detected, scanning stops until the key is released. the pressed key is encoded and placed on the d out pins, and the data avail strobe is set high. when the key is released the data avail strobe is set low and scanning continues.
turning ideas into reality abcircuits www.abcirc uits.com pob 123 new hill nc 27562 (919) 290 - 7104 part number KBDP64 february 2013 page 7 of 7 physi cal dimensions design services available we can quickly turn you r idea into a chip, a pc board, or a finished product. contact us with your needs and specifications.
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