flashing a 93c56 EEPROM with arduino

Just as the title states I wish to flash a 93c56 EEPROM in my jeep cherokee gauge cluster because my old gauge cluster has malfunctioned and the new one will have incorrect millage on the odometer. Is this something the arduino can handle? And if so how would I go about doing this?

Writing to the eeprom isn't too hard if you have access to the pins. Just bit-bashing.

But what is the format of the data?


No clue how do I go about getting this info? I know this guy here did it with an off the shelf programmer, which is quite expensive compared to the arduino I all ready own.

Here's the datasheet.


you need access to the CS, SK ,DI DO, VCC and GND pins. Is there a connector next to this chip which does this?

I'll see if I can find my old bitbasher - but given the datasheet you could figure it out.

Given that it's 'in-circuit'- I presume soldered - you'll probably need to break the leads to CS, SK ,DI DO,

so as to prevent the existing curcuitry from preventing your operations.

Since I dont know the format, and this chip may contain lots of other data, the first thing I'd do is download it's existing data into a fiole, and see what's there.

But not that easy.

If you had the appropriate sw from the manufacturer I bet you could do this via the OBDII connector - but I also bet they're not telling you how!

It may be cheaper and less risky to go to a Cherokee dealer and get him to do it...




Well the good news is its a late model and I have everything I need from a junkyard for very cheap. Ill see what I can do about separating that chip. If I do go about pulling the code, is there a circuit that needs setup and any pre written code for this?

I'll dig out my code is you like ( written for an 8051, but easily translated) - but that doesn't help the format problem - please talk to the Cherokee people -they may be helpful.... surely this must be a problem they have to deal with occasionally. It won't be easy, as they don't want crooks 'clocking' the mileage.



Hi, What do the professionals do when they need to change instrument cluster? There must be a procedure to clone the new cluster from the old.

Have you asked? Have you googled?

Tom... :)


google cloning instrument cluster eeprom


A stack of stuff.

Tom... :)

I actually did do some googling and most people either take it to the dealership or reflash it with an EEPROM flasher. I just figured why not try with my arduino and learn a thing or two. Not to mention so many people in the jeep community have arduinos and would benefit from this. I'll look into that cloning. I just wonder if moving the chip might be a solution.