General ECU hardware questions ....

[silverpike]

Hi guys, I have been lurking here for the most part. When I owned my Honda months ago, I used to do a lot of hacking with the PGMFI.org guys.

Since my baby is gone now and I have an 02 bugeye, I am very interested in all the hard work going on here. There are just a few questions I have that don't seem to be addressed anywhere on this site.

1) Can someone crack open a USDM WRX ECU and take some hi-res photos of it? I don't have a spare ECU to do this with. I am curious about the parts that are used. In particular, I want to evaluate how hard it would be to socket the onboard flash, in order not to worry about limited reflashes.

2) Looking thru the ROM dump code, can we identify which of the microcontroller outputs are being used, and which are available? The PGMFI guys had great success in using stock-unallocated outputs to drive extra devices, like wastegate solenoids, nitrous, and what have you. Even better if these outputs are already tied to pins on the wiring harness.

I am aware that the more recent STI ECUs use the Hitachi SH processor, so this information will be different for those.

Keep up the hard work guys.

Ken

[cboles]

1) There is no external memory in these ECUs. I think the erase-write cycle limits of these parts are rated very conservatively, so most people won't run into a problem typically. All of the reflashing code I have written for the HC16 and SH processors follows the manufacturers specs and adaptively applies the minimum flash pulse durations needed to reliably burn the bits without putting excessive "wear" on the flash. You can always reference maps in RAM if you want to do a lot of tweaking without burning the flash.

2) I haven't spent the time to do this, but it is not that hard to do. From the hardware side, you can to some degree see what is connected to what on the PCB and compare it to the data sheet without removing the CPU. On the firmware side, it's not that difficult to disassemble the code and find all references to the various port registers and from there look at the bit masks to see what is being used. Adding your own code in takes a bit more understanding of the program flow.