Petit_FS for battery-powered recording.
The Petit_FS has worked great for me. I used the 43oh SD card booster pack to get me started. Step 1: MSP430G2553 on a Launch Pad. Step 2: port code to an MSP430F5529 Launch Pad with the same booster pack. Step 3: port it to our own MSP430F5529 board with a micro sd card on it. The only changes were for port assignments and clock implementations.
The Petit_FS works for write, read, and multiple files.
To maximize battery life given the micro sd card's 100-200 ua standby current, we power it down with a FET, then reinitialize it before we wr
