MSP430G2955: Flash corruption possiblities

Hi, Srinivasan

If Vcc is within MSP's spec, Falsh operation is OK. Flash has internal charge pump to do Flash operation.

I think internal charge pump have enough time to do flash Wirte and Read operation while Vcc is suddenly brown-out.

Regards,

Helic

The main issue we saw in our product, some times Data stored in information memory corrupted some time Interrupt vector segment corrupted some times one or more segments of code memory corrupted  - mostly filled with 0xFF some times only few bits in a 512 byte segment corrupted.  

Mostly this issue happened when the device operated for a while with the operating voltage level is below 2.2 V until the battery is dropped below 1.8 Votls

So, that I just want to clarify, what will happen if we keep the micro controller run between 1.8V and 2.2V for a while and do some flash read  / write operation max of 5 times per day.

Is there any possibility for above mentioned flash corrupted (Information memory / Interrupt vector memory / program memory) when we are trying to do any flash read / write operation with this operating voltage level (between 1.8V to 2.2V).  

Datasheet mentioned that Flash Write / Erase requires minimum 2.2V.  What about the minimum voltage level for the read operation.  Is there any possibility for memory corruption due to Flash read operation with this input voltage level of below 2.2V.

Hi, Srinivasan

Srinivasan S said:

Is there any possibility for above mentioned flash corrupted (Information memory / Interrupt vector memory / program memory) when we are trying to do any flash read / write operation with this operating voltage level (between 1.8V to 2.2V).  

No. If Vcc is not in Flash write spec 2.2 ~ 3.6V, it's impossible to write and erase.

Also, Figure 1, Safe operation area need to be taken into consideration.

Srinivasan S said:

Is there any possibility for memory corruption due to Flash read operation with this input voltage level of below 2.2V.

It's possible to read Flash when Vcc = 1.8 ~ 2.2V.

During program execution, Flash is also read by CPU. (Code store in flash in default).

Regards,

Helic

What could be the possibility for these kind of memory corruption on MSP430G2955?
a) Information memory corruption
b) Interrupt vector memory corruption
c) One or more segments of code memory corruption - mostly filled with 0xFF some times only few bits in a 512 byte segment are corrupted

We found these event triggered on some devices - went offline due to complete battery depletion. When we pick the device and replace a new battery - they didnot start working. Then we read the memory - the memory read data indicates these three type of issues on those devices are not working after battery replacement.

Note: We don't not have any protection for device operation in extreme low battery level. The highest current consumption on the device is RF TX / RX which consumes nearly 20mA current for max of 10ms.

Hi, Srinivasan

All of these address range is Flash, and corruption possibility is depending on the frequency that you write/erase these Flash regions.

Also, for Flash read operation, if Vcc is below 1.8V, I am sure whether flash data corruption will happen.

This function may help you halt CPU when battery is too low to drive your system:

    User's Guide: Chapter 9 Supply Voltage Supervisor (SVS).

Regards,

Helic