Hacking VFD display Key Scanner with an Arduino

Thread Starter


Joined Nov 5, 2015
Hello all, I'm wondering if anyone can help me figure out how to talk to a Sanyo 75700 key scanner IC. The key scanner uses Sanyo's CCB protocol as outlined in the data sheet with a Chip Enable, Data In, Data Out, and Clock line. The chip interfaces with a Renesas M30873MHA microcontroller. My ultimate goal is to use an Arduino (or whatever works) to mimic the output of the key-scanner and send it to the microcontroller. The key scanner is hooked up to the button contacts on the faceplate of the radio. So as far as I can tell, when a button is pressed, for example the FM/AM button, the microcontroller reads the DO line of the key scanner and the mode or changes. Of course that is only speculation because I have yet to figure out how to read this line.

There is a CCB library for the Arduino which I've loaded up. I hooked up just the faceplate and powered up the chip through the same connector that normally connects the faceplate to the radio (see pic). After that I tried running the Arduino to read the DO line while pressing different buttons on the faceplate but it seems like it's not reading anything out. The DO line does have a 10k Ohm pullup resistor but that is also powered up via the 5V line.

Any ideas?