Honda Civic 2008, memory chip 93C76 issues

[Aver8geGuy]

Hi

I'm looking to change the mileage in a replacement cluster due to the original one going faulty, but I'm having issues writing to the chip. I have read it in circuit with UPA-USB Device Programmer S and in-circuit adaptor I've used for other devices and that seemed ok albeit the mileage displayed doesn't correspond to the data in the dump but at the moment that is the least of my worries.

I was having problems with the UPA-USB reading until I read a post about changing USB cable and that now seems stable. Problem was I tried to write to the chip a new dump but when I read it back it's a combination of all 02 and 03's. I've tried the erase and then that reads back as all FFs. However as soon as i try to program it again it reverts back to 02's and 03's.

I'm assuming while my programmer was playing up I have corrupted it or can these not be written to in-circuit? I've yet to remove it and try it. Are they just normal 93C76A devices with normal pins? Just having trouble locating some replacement ones in the right package....can't make out's if it's SOIC8 or SOP8 package....not much between them.

Any advice on programming these would be appreciated. I've set the programmer to 3.3V as that works ok with the read, anything higher causes an error.

The attached dump was taken before I attempted to program it. The value of "13 13 EC EC" is suppose to be 48021 miles but not when I work it out, but can worry about that once I've managed to reprogram it back with valid data.

Cheers

[clusters]

That dump is read wrong, you need to read it as 16 bit. If you have overwritten it then you need a new dump.

[Aver8geGuy]

Clusters, thank you for your reply. I've looked at a number of other dumps in this forum for the same vehicle and they look similar to mine. Is there a way to tell I have read this as 8 bit rather than 16 bit?

Will I be able to recover this device if I write as a 16 bit chip or do you think it is damaged now?

Thank you

[clusters]

Did you write a file to this dash? If you did it is unrecoverable, you need a new dump.

I can tell it is read as 8 bit because of the repeating bytes.

[delu]

when i try to read the original eeprom undesoldered (93c56, 93c66, so on) and the milleage displayed is not correct i always make a bridge with a wire on the quartz if the board has one, then the read will be ok.

[fuzz1]

Think that's the way to read in circuit

[Aver8geGuy]

Did you write a file to this dash? If you did it is unrecoverable, you need a new dump.

I can tell it is read as 8 bit because of the repeating bytes.

Yes I did write the file to the dash....luckily it's the old dash that has a fault on it so was just using it to experiment/practise before I reset the replacement one. I found I could change the mileage values and they would work out to within a hundred miles of what I calculated so useful test for me.

I've now written the old mileage to the new dash in circuit and shorting out the crystal. The dash is displaying a slightly different value (<900 miles different) than I was getting on the old dash when experimenting so I guess the dash has changed it for some reason but its closest enough not for me not to mess around with it anymore in case I damage this one!

Thanks for everyone's help......we now have a Jazz with the exact same fault so have a replacement dash coming for that and I'm hoping it's very similar :)

[fuzz1]

Close enough is good enough in this case. I have never really understood how to convert the hexadecimal to decimal values either. Tried all sorts of combination little endian big endian reversing the bytes. Gave up. I just get something close to the value not the exact.