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42 Key Keypad on 5 wires (Complete)
This all started here in this thread.
I was having issues adding an extension to the standard 4X4 keypad in an effort to expand it with more keys. Even with the inline and pull-down resistors prescribed I was still getting cross-chatter.
The conclusion that I came to was that I needed to abandon the keypad and make a completely new one that uses diodes to prevent cross-chatter.
Several users helped and a couple of them really pushed me with new subjects to read and understand. I'm grateful for their contributions.
This is the result.
I arranged it in a 12X4 array. Thanks to VIRAND I will use a CD4040B ripple counter for the 12 input pins. I will run this with a single clock pin and no reset. Effecting a 5 pin bus that needs no resistors and suffers no power loss. Resistance is futile.
Each switch receives power from an input pin through a 1N4148 diode and passes the signal of another switch. This create a 4 bit output bus.
Each 4 switch row is read sequentially, one at a time buy pulsing the clock pin on the 4040 ic.
The spin software should be a bit simpler than the 4X4 software as it does not have to increment though input pin numbers. This will make it a single, simple loop and eliminate the frame references from multiple methods.
Due to a poorly written advertisement, my 4040s are delayed until Friday evening. So now I have to wait.
Shout-Out to Cluso99, WBA Consulting, and VIRAND for all their help.
Any comments, questions?
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