This is a 16-key matrix keypad project using the 74c922 16-key encoder ic (circa 1995) . The wiring is straightforward. The 74c922 datasheet shows the Truth Table on pg-4 and the layout and wiring on pgs. 6 & 7. Rows 1 ,2,3 & 4 are ic pins -1,2,3 & 4 respectively. Columns 1,2,3 & 4 are ic pins -11, 10,8, & 7 respectively. OSC cap is 0.01 uF on pin-5 of ic. KeyBounce Mask (KBM) (debounce cap) is 0.1 uF on ic pin-6. Vcc is pin 18. Gnd is pin-9 DATA_AV (Data Available) is ic pin-12 and goe...
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