Is there a cheap programmer than can read from/write to SRAM style memory?

[alank2]

Hi,

I've got a friend with one of those battery backed up SRAM's in a scope for calibration data.  If he gets a new part, is there a simple tried and true usb style programmer with a ZIF socket that can read data from the old and write to the new?  It has address lines, data lines, OE, RD, WR.

Thanks,

Alan

[james_s]

The common TL866 can read and write some of them. You do need to be careful though, I pulled the DS1644 from two different TDS340 scopes, read it, reinstalled and it had lost the calibration constants. Beats me why, the data it read looks ok, and by writing it I could set the time and date back to the values I had read from the chips. It's possible the battery was just marginal enough that heating up the pins corrupted the data, I don't know.

[David Hess]

The common TL866 can read and write some of them. You do need to be careful though, I pulled the DS1644 from two different TDS340 scopes, read it, reinstalled and it had lost the calibration constants. Beats me why, the data it read looks ok, and by writing it I could set the time and date back to the values I had read from the chips. It's possible the battery was just marginal enough that heating up the pins corrupted the data, I don't know.

The same thing happened to me when I read the Dallas NVSRAMs from my 2440.  The programmer I used worked correctly with the replacement memories and I never resolved what went wrong.

[james_s]

Anybody know if there's a way to dump the NVRAM contents of a TDS340A over GPIB as can be done with the TDS500/700 series? I have an option 14 board in one now and I can control the scope but I haven't figured out how to read the RAM if that's possible. This one passes all the self tests without errors so I'd like to make sure I back up the DS1644 without losing the contents at which point I'll graft a new battery onto it.