RAM status during Watch dog timer

[MFC52259]

Hello,

I am using Cold fire MCF52259 in our project. 

I wanted to know the status of variables declared in RAM

during the Watch dog timer reset.

Will the variable restore its value on next power ON?

[mjbcswitzerland]

Hi

See also http://www.utasker.com/forum/index.php?topic=631.0

Regards

Mark

[admin]

mjbcswitzerland gave link to excellent explanation for SRAM.

But, content of DRAM isn't guaranteed to be preserved due to suspending of the refresh.

Note, that the start-up code regularly include some memory test, which overwrites the SRAM or DRAM content.

[AloysiusJegan]

Yevgenit,

Is it not possible to stop memory test during soft reset?

Jegan

[admin]

I believe, any good start-up code has a few defines, which customize the behavior, including enable/disable memory test.

See the source code of your system start-up module. It's possible, that on-chip SRAM isn't tested at all.

[AloysiusJegan]

Yevgenit,

Thanks for your input.

Jegan

[admin]

Based on my understanding of how CPU and RAM work, I can tell you that RAM contents will be preserved during watchdog reset. Of course, you'll have to make sure that startup code doesn't overwrite the variables you want to preserve.

Message Edited by scifi on 2009-07-17 08:30 PM