I am not using a micro controller. I am building my own custom logic in an EPLD (namely the MAX 7000A from Altera) and using that to build an interface to the RF decoder I have as well a couple other things not related to the keypad interface.

Thanks! I was thinking along that line, but was just confused on what I was seeing on the scope, but I will operate off of your explanation and keep you posted as to what happens.

Thanks again!

Yes, I am more interested in how the keypad interface works in more detail, speaking from an electric standpoint and not a high level one as found in the user manual. I need to know how it responds to keypresses so I can build the proper circuit to translate the 8-bit value into what the keypad ...

I need help on an issue concerning the concept of operation of the keypad interface on the LK202-24-USB-WB. I scoped a keypad I had hooked up to the C1 and R1 pins on the keypad interface header on the LCD module and noticed the spike down (when a key is pressed) and the up (when the key is ...