I'm interested in reprogramming an automotive ecu in my car. The processor is a 6502 and the car is a toyota product. I've seen websites that show the processor in this particular car does use internal memory and requires a daughterboard to recalibrate for larger injectors, turbocharging and altering fuel/ignition mapping. My issue is I need some guidance in the accessing the internal memory (dumping the rom) and forcing the cpu to use external memory. I've done this sort of thing with my nissan ecu but that's a different processor and uses an eprom which made things fairly straightforward for a mechanical guy like me. Does anyone have a website or some info that would start me on my way?
Thanks, Bernard

Hi Bernard,

A stock 6502 does not have internal ROM. Your IC probably uses a 6502 core with built-in memory and purhaps RAM too. If you can provide all the info from your particular IC, we may be able to help you.

Include the manufacturer, entire part number, and any other numbers in the IC.

Thanks!

Daryl

It's actually a 6520. My mistake. Full part# is d151801-6520 also has 7616-2024 and 8d1364 on chip. This is from a 1987 model Toyota.
Other chips on board are:
22 pin dip d949577-2100 also has 3894-88(B?)2121
16 pin dip td62504p
24 pin dip 151821-0021 also has 819ah
14 pin dip tc4069ubp also has 8820hb
20 pin dip ND MF 169 also has 5h14b
I can provide pix as well if that would help.

Hallo Bernard,

>It's actually a 6520.

That is an I/O chip, no CPU.

> Other chips on board are: ......

I don't recognise these numbers at all and I'm afraid that the 6520 is just another factory code. The only thing that could help is to find the original (EP)ROM and to make a dump of it. One of us could see in second wether it is 6502 code or not. If it isn't, some of us could compare it with Z80, 6800 or whatever other CPU.

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That's the problem,,, I can't see any of the chips as being an eprom to get the code from. I've reprogrammed many ecu's but this one is strange in that there doesn't seem to be a cpu. Perhaps there's another ecu in the car somewhere. Oh well, I'll move on then. Thanks for looking.