I have a core hooked up to an MP3 breakout board (VS1053), and an RFID breakout board (RFC522). I also have a hall effect sensor that I use as a wakeup interrupt.
I’m trying to save power by putting everything to sleep. Here’s what’s happening:
- When everything is running, it consumes 180mA
- When I put just the core to sleep, it consumes 55mA (I believe because the RFID and MP3 board are still awake)
- When I put just the RFID to sleep by driving it’s reset pin low, consumption goes from 180mA to about 165mA
- When I then put the MP3 to sleep, current goes down to about 153mA
So far, so good. The problem is that if I put the RFID to sleep, then the MP3 to sleep, then the core to sleep, it still consumes 55mA.
My theory is that once I put the core to sleep, it doesn’t hold the reset pins of the daughter boards low. Maybe the go into high impedance mode, and the daughter boards wake back up?
Any thoughts? I need to get the whole thing down to under 2mA while sleeping.