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fenugrec / nissutils

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rename alt_start / end ? #19

Open fenugrec opened 3 months ago

fenugrec commented 3 months ago

zb060 A2L calls these P_HiROM_BG , P_HiROM_EN

Robo-Kronos commented 3 months ago

I've learned a LOT more about ECU/ECM architecture and the chips that power them as the microcontrollers, since our last exchange. I never did look further into our discussion on the custom software. I still own the Nissan but it's been sitting with a dead auto tranny in my back yard.

I've come across your work several times in my foray into the worldwide world of tuning/Altering the engine systems. So for all of your hours and years of work, thank you. I would thank you with a donation, but I am broke without a job since January. Hence learning enough hopefully to start doing my own tuning business..

The two items above for the high ROM and the BG look very very familiar to the power PC chips by Motorola that are in a good number of GM and a lot of other makers ECM components. They're basically just power PC platforms My Cadillac that I'm working on now runs off of the MPC 5676 (Motorola Power Computer 5676). And if you take a look at the chip directly they meeting Motorola provide all of the diagrams and schematics and how to program them like in the most basic ground level of ways. And on the newer chips they always have a higher register area of memory a lower register area of memory and some have more than that I'm guessing background and then of course the main operating system and whatever else that they need they can pretty much just add to the design. I hope this insignificant info might guide you to the right spot. I have the documents on my cars 5676 and some code warrior examples if you would like me to share a link. I'm fairly certain they are public domain. Nobody would even know that it goes into a car just from looking at the papers.

fenugrec commented 3 months ago

Thanks for dropping by;

The two items above for the high ROM and the BG look very very familiar to the power PC chips

That's possible of course, but this series of ECUs made by Denso have a long, long history of using SH705 mcus which have very little in common with PPC. I take P_HiROM_BG and _EN simply to mean "program, high ROM, begin / end". This corresponds fairly well to the way I've been handling this alt_start/end block checksum. Of course, I can't say for sure that the naming didn't originate from an earlier PPC codebase, but the SH705 has a nicely flat memory space with one contiguous ROM range, and any low/high distinction would be purely at the firmware level as implemented by Denso.

Anyway, this ticket is just a minor, non-feature TODO item for me to do someday when I have time and motivation.

Best of luck in your projects, hopefully the tides will turn in your favour