Quote Originally Posted by Acetronics View Post
Hi,

I'm not really sure ... BUT

something like this was done by the Honda Civic enthusiasts. But they change the EPROMS manually ...

Now ... something also has been done with PICs and RS 232 ... But the Pic ( a 16F88 ) is using the tables " for himself ".

I do not think a Pic will compete with 27C access times ... do you ???

let's think to a Pic loading 1/4 of a 27C512 ... with engine compulsory OFF ( remember : the bus must be shared between PIC and ECU !!! )

My point of view : an idea to forget quickly !!!

Alain
You are right about the access times of the chips Vs a pic, somewhere in the 90 to 120ns depending on manufacturer but I dont know fast the ECU will read off the data, I doubt it will be running as fast as the 12C is capable. But I've never played with ECUs so what do I know It may just read the wrong data because the pic is not fast enough and move on to the next address. That's why I think changing the rom externally would be an easier way to go.
Without using any algorithms I can copy a 120ns 12C512 in about 11 seconds so writing to every address in a 12C128 should take less than 6 seconds, even quicker if you are only going to change a few addresses.

A quick search turned up this site

http://www.i-club.com/forums/vbartic...le&articleid=4

I don't have the time to read through it but it may give you some better ideas of what other are doing.

Regards,

Paul