I am working on a project in which we are using the MSP4305969 to measure temperatures and write data to an SD card. The datalogger is in a remote location, so the system needs to conserve enough power to log for a full year. In order to do this we are logging only every 15 minutes and powering everything down to a sleep mode between measurements. We use a transistor as a switch to take power away from the line of temperature sensors while the board is sleeping. That all works fine, my issue is with the SD card reader. We are using the "slot socket" for arduino
and the Petit FatFS library for writing to the card.
When the SD card reader is wired directly to the board the system works fine and it writes exactly how I want it to. However, it draws too much power. I tried wiring the SD card reader through the transistor so that it will have its power taken away when the board is asleep. This creates an issue in writing to the card. It seems as if the SD card reader needs some startup initialization time before it can properly write. I have also tried having the logger pause between waking up and writing, that didn't help either.
If anyone has any advice it would be greatly appreciated.