Couldnt really find a section for this..

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Re: Couldnt really find a section for this..

Postby oldn64 » Fri Aug 17, 2018 12:45 pm

antus wrote:So they're sets of 4 lots of 4 16 bit values (aka words. 16 bits = 2 bytes). So ignore the first 4 words and where you see AC53, thats 53AC in the tool. This is due to different computer systems ordering. Known as LSB or MSB (least significant bit, most significant bit). I think Festys tool has swapped some of the stuff around for you, but you can see 3 copies of 4 words that match the tool. So put the new value in, hit calculate and update all 3 copies on the rom, manually swapping the bytes in the words around. hit save. Flash to chip. Solder to board. I think the 3 copies are part of basic error detection and recovery logic. If one copy is found by the dash to not match the other two, the dash will update the mismatching copy to match the other two. This way a single bit corruption is recovered and the data is not lost. In theory if you updated 2 copies the dash would do the last one for you in the car... The first section is likely trip computer or similar, but I dont know.


Woohoo something I can assist with. Essentially the above is correct it also depends on your writer as to what why you enter this. Generally if the read displays as yours it will write in that format. You will need to swap each pair of bits. So in your example you have the stream

53AC F30C 9D62 5D2A in the read from the dash you will have AC53 0CF3 629D 2A5D.

So to update. Type the new klms into the dashtool. this will through out the numbers you require. For example - 864321 klms would be.....

57A8 9E61 3DC2 7B84 so you would place into the bin from offset 0x00000008 - A857 619E C23D 847B A857 619E C23D 847B A857 619E C23D 847B then save and right the file.

The three copies are a crude form of correction and checks. It does two types, first it will do the 2 byte check to see that the message is correct then it will move to see whether the data is the same between all three. From memory it goes and looks for the first one if this is correct looks at the second if this is correct then looks at the third. If one or two of these are not correct it will use the others. If there is two correct but different ones it uses the higher klms and copies across. To be safe just write the correct bites into the chips locations.

The first 16 bits describe the version and options for the dash, things like klms or miles, 60litre tank or 80 litre tank, and the speedo correction. the speedo correction can be adjusted via the menu options and the fuel tank size is changed via the switch on the back of the dash. so changing these will technically get changed back due to other outside sources.

For reference I have attached my VQ statesmans string read from the dash which got burnt. I plan to just drop this back into a new cluster to get my dash working again. My system does not swap the bits so it will look different to yours. Klms on mine are 180327.

1071 3F00 FF00 07A0 42BD E718 3FC0 1BE4 42BD E718 3FC0 1BE4 42BD E718 3FC0 1BE4

thumpa 180327.JPG
thumpa 180327.JPG (18.36 KiB) Viewed 289 times


I also have an other one which was pulled from a HSV89 - 0101 D926 FF00 DF20 39C6 E31C F906 DF20 39C6 E31C F906 DF20 39C6 E31C F906 DF20

So just do your update and then put back in. If you get 555555 klms then you have done something wrong. I would test on your original dash first to get the hang of it :)....!

I then went searching for your original thread and found that this might happen to be the old dash as the photo you had was for 304623 klms. So the main thing here is if you are doing this on the new dash make sure it is swapped and then generate the file appropriately, do nto change teh first 16 bits and all should work out a treat. Compare with the tool before doing a thing. if you need help yell :).


cheers
oldn64

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Re: Couldnt really find a section for this..

Postby j_ds_au » Sun Sep 23, 2018 10:59 pm

Biggvl wrote:oh, to confrim, that chip is from the 104 location...

IMG_0330[1].JPG

Lovely pic. If you have this handy, would you be able to assist resolving a mystery from early in this thread? Would you be able to check with a multimeter whether there's a connection between pin 1 of CN103 and ground?

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