This is where the BIN Hackers and definition junkies discuss the inner workings of the EEC code and hardware. General tuning questions do not go here. Only technical/hardware-specific/code questions and discussions belong here.

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Gear Head
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Joined: Mon Jun 25, 2018 9:18 am

DIY memory chip

Post by rezor » Fri Aug 17, 2018 5:04 am

because I swapped my mustang transmission to manual i want to reprogram EEC also :P Because installed EPROM is not typical one that I can reprogram in easy way, I started to investigate how it works. EECTCH98 documentation and eecsucka project was really useful so I want to try create my own j3 chip with xilinx CPLD with T4M0.bin on it. Because of that i have some questions:
1. Will EPROMDISABLE HIGH simply disable eprom to avoid interference? Or do I need desolder eprom completely?
2. What is maximum possible delay between strobe signal and correct output provided by eeprom? I'm wondering how fast chip should be to avoid situation when old data will be read twice by cpu
3. I have flash memory also in my EECs: 81C65 on W4M0 and 81C62 on C4P0. They have any purpose?

I'm not interested to buy QH or PnP stuff because I have already SA ECU for my project. I just want to do this for fun :)

Gear Head
Posts: 34
Joined: Wed Jul 02, 2014 3:02 pm
Location: Vancouver, WA.

Re: DIY memory chip

Post by Jman » Wed Feb 21, 2024 4:02 am

I found an some interesting J3 memory adapter information posted by Ender11 from about 10 years ago (Link below). Very impressive project with pictures and CPLD code download RAR file. You may have to translate the language from this page. I also would like to build my own J3 adapter. I have lot to learn about CPLD's and hardware programming language first. I will try to just copy others work as in this link and Andrew March to learn from. I think that's probably what Craig Moates also did in his beginnings. I would love to know more about Craig Moates background not sure if it was all him or if he had other minds helping him develop all the different products his company sold before they closed down.

I don't think you would need to remove your ROM chip to use an external memory adapter because any of the commercially available plug and play type J3 chips work without having to remove the original ROM chips from the EEC. ... &start=180

Thank you

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