RAM retention after hard reset

Ushan Karunathilaka

Intellectual 695 points

Other Parts Discussed in Thread: MSP430F2418

Hello,

I m using several "no init" variables in my MSP430 program and those are initialized only after power on reset.

i observed that sometimes those variables have garbage values after a hard reset.

there is no power supply fluctuation during the reset period.

please help me...!

Ushan

over 14 years ago

0 Bernhard Weller over 14 years ago

Genius 4925 points

I'm not sure on this one, but I think TI does not guarantee the validity of data in case of a reset. Maybe you can add a checksum for your critical variables, and if that checksum is not valid after a reset you can initialize the values to be safe.

0 Ushan Karunathilaka over 14 years ago in reply to Bernhard Weller

Intellectual 695 points

Hi Bernhard,

TI indicated that the RAM will be retain if the voltage is above 1.6V.(page 71 of MSP430F2418.pdf)

RESET does not initialize the RAM. therefore, if the circuit is electrically okey RAM should be retained.

Thanking You,

Ushan

0 Bernhard Weller over 14 years ago in reply to Ushan Karunathilaka

Genius 4925 points

Well you see, the test condition is "CPU halted", but what happens if the CPU is just writing something to the RAM or reading from it when the reset occurs? I don't know but I can imagine that something can go wrong in that case.

But maybe someone else knows more about that.

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RAM retention after hard reset