Couldnt really find a section for this..

[festy]

Which model car is that chip from?

Apparently a VP calais

[festy]

This is a bit more promising...
After issuing a read instruction, the MSB is read *before* clocking, all the other bits are read while the clk is high.
I noticed that in the datasheet's timing info, but didn't think they were serious
It makes a big difference though - I noticed that the combined digit checksum didn't add up, and there were no odd words in the read data... as if I was missing the first bit which would make the 16th bit always 0 - and thinking about it, the individual checksums would still be vaild for the effectively left shifted word.

Code: Select all

READ:
addr: 0:31611
addr: 1:25765
addr: 2:255
addr: 3:1275
addr: 4:7905
addr: 5:13515
addr: 6:13515
addr: 7:31110
addr: 8:7905
addr: 9:13515
addr: 10:13515
addr: 11:31110
addr: 12:7905
addr: 13:13515
addr: 14:13515
addr: 15:31110

or in hex:

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7B7B 64A5 00FF 04FB 1EE1 34CB 34CB 7986 
1EE1 34CB 34CB 7986 1EE1 34CB 34CB 7986

Remember the odo was 343479, just read off the digits - 34CB 34CB 7986
The individual checksums are good, and the all-digits checksum is valid (well it's decimal value is at least)
Reading the eprom in the native endian data format means no need for antus' lookup table.

Now to code the write instructions, then a windows frontend GUI

[The1]

good work festy

Goes back to counting sheep..

[Doctor Bob]

do you guys want me to take some pics inside a VDO resetting tool?

[The1]

would be interesting to see.

[The1]

Fairly sure the ebay ad said x24c44 via ICSP only, so you can't use the ZIF socket.

Yep if you look at the photos of the board it has a icsp 10pin header, so i guess i just need to figure out what pin to pin

[festy]

It's just a case of providing vcc and vss, the sclk and di/do lines, pin 6 and 7 pulled high, and ce is active high but needs to be cycled between each instruction.
I'm surprised that the 93c socket won't work, but it might have a hardwired ce line or something.

I've added ram write and eeprom store instructions to my code, so might try hand-editing a bin with hyperterm and calc tonight, to test my checksum theories before I worry about a frontend.

[The1]

yeh i tried the 93 socket, no change.

[festy]

If all else fails I'll swap you for one of mine

[Doctor Bob]

if i can get one of my programmers to read it ill post the file.

Rob