Electronics > Metrology

Battery backup RAM reading

<< < (2/2)

Le_Bassiste:

--- Quote from: uncle_bob on January 29, 2016, 01:57:39 am ---Hi

A lot depends on exactly what happens to the device that normally *drives* the RAM when the RAM is running on battery. It's probably not a good thing to read the RAM and blow out the gizmo it's attached to. Most of the time this involves powering the whole thing up and holding the MCU (or whatever) in reset while you read the RAM.

Bob

--- End quote ---

you probably misunderstood my statement. i didn't "drive" any lines in the unit. it wasn't even necessary to hold the MCU in reset. i simply "sniffed" all the pins of the RAM while exercising the unit in its different operating modes.

Kleinstein:
The first choice would be getting the calibration data through the normal interface (GPIB,RS232,..).

Otherwise it's up to keeping the CPU in Reset state and hope one can takeover the bus. Or just sniff the normal operations.

uncle_bob:
Hi

The limitation to the "normal operation" as compared to the "takeover" approach is the assumption that you can catch it reading everything in a finite amount of time. With some of my code, you would have to wait a couple of days to get it all in normal operation.

Bob

Le_Bassiste:
 i was lucky not to come across any of your code in my HP3468A :-DD

uncle_bob:
Hi

All of my stuff is buried in some pretty obscure places. There's a lot of it out there (pieces wise). You just are highly unlikely to ever run into it.

Bob

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod