Offsets when burning different EPROMS

EPROM EEPROM SRAM NVRAM Flash chips, reading/writing hardware and software
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Re: Offsets when burning different EPROMS

Post by vlad01 »

So other than filling the eprom up, what the actual purpose of stacking?

Does the ECU not always read from 0x00 ? can't you just write the bin once at 0 offset and be done?
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Re: Offsets when burning different EPROMS

Post by VL400 »

For 64k or less bins, it must end at 0xFFFF. The last two bytes (0xFFFE and 0xFFFF) are the reset address for the processor to know where to begin running code from.

If your EPROM is larger than the bin, burning with 0 offset and no stacking will mean full limp home mode with no code running.

You need to stack the bin to make the resulting bin the same size as the EPROM and not worry about any math, or burn one bin with an offset so the bin ends at 0xFFFF - ie 16K $5D bin on a VR auto memcal with 27C512, offset would be 0xC000 (0x10000-0x4000 = 0xC000).

Either method does the same thing in terms of how it will work in the ECU, just that one method means you need to understand hex and the other simply stack until it makes a file that matches the EPROM size - which TP has a really simple way of doing as shown by holden202t earlier in this thread .. http://pcmhacking.net/forums/viewtopic. ... 343#p38348
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Re: Offsets when burning different EPROMS

Post by vlad01 »

Ok that makes sense now. So its the end of the file at 0xFFFF thats important?
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Re: Offsets when burning different EPROMS

Post by antus »

Yep. Reset vector. It'll be a 16 bit (2 byte) address. And the computer will jump to that address and start executing at power on. All the internal addresses in the code assume the file will be loaded at the top of the address space (known as top justified, in tunerpro terms). Once its sitting in the right spot your good to go.
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Re: Offsets when burning different EPROMS

Post by vlad01 »

Cool, thanks for the clarification.
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Re: Offsets when burning different EPROMS

Post by vlad01 »

Trying to burn a tune to a STTSF27512 but the car wont run other than limp home.

So after looking at different tunes that worked fine I noticed my tune appears to be the cal only and OS part missing.

How do I get the file from TP to save the whole bin as well? Some files I open and save are complete, but my tunes for the VR and my VP are incomplete BINs

Yes, I have stacked it, the stock BIN files stack and work fine in the car.

Any ideas? :think: This one I unloaded isn't stacked in case you are wondering.
Attachments
OSE $12P V112 BLCD V6 VP vacationer.bin
(32 KiB) Downloaded 399 times
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Re: Offsets when burning different EPROMS

Post by VL400 »

Use the flashtool and get bin.
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Re: Offsets when burning different EPROMS

Post by vlad01 »

haven't got any of the hardware on that car, using old school EEPROM and burner.

Anyway, I reckon I got it. I open the stock BLCD bin and loaded the tune in the bin compare. Used he difference tool to copy all the cal stuff over and left the OS part untouched. The difference tool indeed showed my tune had empty OS section. So I just burned it to the chip as it is with 0x8000 offset. Fingers crossed!
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Re: Offsets when burning different EPROMS

Post by vlad01 »

Good news, no more CEl and limp home but wont start, I reckon I have the VATS on as I did borrow the tune from the VR. Going to have a look now.
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Re: Offsets when burning different EPROMS

Post by vlad01 »

All good, working now. Geez this tune is considerably better than the old one.

Solved my long issue of low power at mid to high revs, it was what suspected, false knock. Plus I have a more accurate VE table and other parameters to suit the engine.

Will add the tune to my built thread. Suits stock VN s2 and VP engines with pacemakers, no bell mouth and better intake, 65mm TB, stock injectors.
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