and doing all the serial communication
Serial communication with what? Not the SD card. That doesn't use serial communication.
at 2.5V (for reasons to do with being very space constrained).
How? Arduinos are typically 5V devices.
and doing all the serial communication
Serial communication with what? Not the SD card. That doesn't use serial communication.
at 2.5V (for reasons to do with being very space constrained).
How? Arduinos are typically 5V devices.