Couldnt really find a section for this..

[festy]

Think I might have just found the dash checksum
Any chance you can read that other dash's chip the same as you did this one?

[antus]

Last time I tried there was checksums for the values, then a global one for the whole thing but you could work around it by swapping bytes, as being just a sum, not a CRC that doesnt break the sums. Can get it ballpark to what your looking for by clicking over the least significant digits then swapping.

[festy]

Code: Select all

    00000000  ff ff ff ff ff ff 00 ff  ff ff ff ff ff ff d3 2c  |...............,|
    00000010  00 00 00 00 00 00 25 da  00 00 00 00 00 00 09 f6  |......%.........|
    00000020

f6^da = 2c
09^25 = 2c
2c^d3 = ff
Probably more to it, but that's definitely a checksum. There might be a CRC check against words 4-7, hard to tell with only one sample.

Does this dash use a 1250ppk VSS?
Because 0x90f6 * 1250 = 3187500

[Streetholden]

Wow, you guys are really into it. Youve got me lost so far. Last time i checked the post i was asked for some numbers and such, went to upload some pictures then saw this.

[VL400]

Yeah you get that around here, lots of keen hackers Nice work festy

[festy]

So getting back to re-programming via connector CN103, it has 5 pins - are they 5v, gnd, and clock,data in/data out to the 24C44, or are they to a uart on the 8051?
I've found an old 8051 of unknown origin to use as a guinnea pig so will try to put together a rom dumping circuit at some point in the future.
I'll need 25 I/O lines to read the 8051 so a pic16f877 would probably do the job.

[festy]

Both of my programmers dont support it So would need to be a pic/avr to read it like festy suggested. Would be interesting to get the MCU code out too

A Willem PCB3 clone should be able to read and write the 24C44 using software version 0.97ja, select "S24H45" for the device.
Or here's an ebay ICSP programmer for $20 that will do them too.

[The1]

Just found the facia for this one I usually label all my parts it had 358100 on it

[The1]

I'll have a look and see if I can read another one tomorrow and do some tracing

[The1]

Both of my programmers dont support it So would need to be a pic/avr to read it like festy suggested. Would be interesting to get the MCU code out too

A Willem PCB3 clone should be able to read and write the 24C44 using software version 0.97ja, select "S24H45" for the device.
Or here's an ebay ICSP programmer for $20 that will do them too.

Cool I'll have a look