Needed - Kepad for counter cct

[Nkosana]

Hi,
I'm trying to replace a lost numeric keypad for a scoreboard using four 7-segment display. My circuit uses a PIC16C621A-04P microcontroller. The inputs from the keypad goes to pin 11 of the PIC and also through a 10K resistor to pin 10. The cct also uses a CD4504BE CMOS Hex voltage shifter, MM74C164N shift register, and MC14511BCP decoder/driver. I do not have a cct diagram and not very familiar with encoding ccts. HELP!!
WILL AN EXTERNAL COMPUTER NUMERIC KEYPAD WORK?

 

[Ian Rogers]

Forgive my ignorance but what's a cct?

Ian

 

[5uco]

Always known cct as an abbreviation for 'circuit'

D.

 

[Ian Rogers]

Well I never!! I've been doing this for over 25 years and never once come across that!!!

 

[ericgibbs]

Always known cct as an abbreviation for 'circuit'

D.

me too, circuit aka cct

 

[OlPhart]

Start with a simple one: "my circuit uses a PIC..." Is it really your design & software?
If yes: reengineering a different keypad is straightforward
If no: you may trace the circuit, but you'll probably never determine the software. You Will Need BOTH to replace the keypad.

I Very recently had to change the RF link on a set of baseball scoreboards designed by a friend who passed away before doing it himself. After a day and half of mapping the uC to the drivers and trying to follow his code, it was obvious that I just rewrite the software instead of trying to put the spaghetti back in the box.

Bear in mind, I had his source code to work from and couldn't follow it! Three days later, (1 for the keypad/transmitter, 2 for the receiver, display & drivers) I had a working system with stable ANNOTATED code. I suggest this to be your shortest path as well. Good Hunting... <<<)))

 

[Nkosana]

Thanks OlPhart. You got me thinking in the right direction. The work doesn't get any easier though. A program rewrite is my only solution.