MSP430FR5972: INFO Memory Segment

Hi Himanshu,

Thanks for posting. You can define an array and set it to be placed in INFO memory by using for example:

#pragma DATA_SECTION(loggingData, ".infoD")
unsigned char loggingData[128];

You can then access loggingData just as you would any array in RAM (e.g. loggingData[x] = 42; //write 42 to loggingData at index x) - since this is an FRAM device not Flash you don't have to do special handling like you did with the flash controller on MSP430F5232. However in this case you will also need to modify the MPU (memory protection unit) settings so that INFO memory has read + write access (default in MPU tool is read-only access for INFO memory). I can give you more details on how to do that if you would like, but first I want to make sure that using INFO memory is the right solution for your use case and make sure that I give you the correct recommendation for what you are trying to do.

I would like to know a little bit more about your data logging - about how much data logging space will you need? The reason I ask about how much space you will need is because each section of INFO memory is only 0x80 bytes. But because this is an FRAM device, you can easily use a much larger piece of your FRAM for data logging if you would like. With FRAM you don't have to do any special handling you had to do on the FLASH device: in FLASH devices the INFO memory was especially important because you had to erase FLASH before you could write to it - using INFO memory allowed you to erase the area without risking erasing your code. On FRAM parts, instead you can use the main FRAM without fear because no erases are needed before writes, and because we provide an MPU (memory protection unit) to prevent you from accidentally overwriting your application code. The MPU allows you to partition main FRAM in up to 3 segments and set the access rights (read, write, execute) for each segment. We've made this simple by providing a method for automatic memory partitioning and MPU setup in CCS. Simply place any arrays etc that you want to be read + write accessible (e.g. logging data) into the .persistent area by using #pragma PERSISTENT.

#pragma PERSISTENT(loggingData)
unsigned char loggingData[2000] = {0};

In this instance, you can leave everything at default in the MPU tool found at Project > Properties > General on the MPU tab (leave it at "enable MPU" and "let compiler handle memory partitioning..."). The loggingData will be retained through power cycles and you don't have to do any further special handling you can just treat it like a normal array in RAM. This allows you to have more data in your logging data if needed and you won't have to do any modification to get the MPU set correctly for your project.

Regards,

Katie

Hi Himanshu,

Glad that I could help! Yes, this looks correct for logging additional data in the other info sections.

Regards,

Katie