Checking and burning data from the Dallas chip DS1230AB-200

[Dalamar]

I found out something that others might find useful with the Dallas chip. I've been sorting out a spare ECU for my mk1 Tuscan and I bought an MBE 941 ECU with an old Dallas IC and no EPROM IC. I sorted out the ECU IC and wondered how good or bad the Dallas IC was (this is the IC that stores the adaptive map info). I could have run the car with the spare ECU, let it run up to temp and settle out with the adaptives, then pull the battery terminal for a few secs and see if I starts up again fine and runs smoothly from the off. In other words, seeing if the Dallas IC retains its memory.

I have a TL866 programmer and I was surprised to see that the programmer could read the DS1230 SRAM IC.

I read my original ECU Dallas IC and was able to copy this info into my spare ECU Dallas IC. Car ran fine on the spare.


I also had another old Dallas IC from an eBay purchase and read the info from that. However, I noticed that if I re-read the info off that IC then it would change over time and this would be reflected in the Checksum. See below pics.



So this is a method to check if the internal battery of the SRAM IC is OK or not. Surprised to see that the Dallas ICs from both my original and spare ECUs are still OK after 24 years! They both retain their info fine and produce a stable checksum.

The Dallas IC date code format is year followed week number. So the chip pictured was manufactured in the 27th week of 2000.

[Dalamar]

Yes it’s the one pictured above and you are correct about the battery only starting to be used on first activation.

The other two Dallas chips I have are old ones both marked 0027C 119057. Interestingly, my ECUs are serialised consecutively.

[Dalamar]

Adrian@, the second image seems to open OK for me. All that I was trying to show with that image is that the checksum is changing every few seconds. In other words, the data isn't being held constant over time as the battery has been depleted and the memory just has random ever changing noise in it.