Low-power mode when inactive

[ManoDaSilva]

Hey! I've been working on a embedded version of BaryonSTM, to integrate it as a replacement for a battery board and get something looking like a Pandora batt. The idea is to have a minimal design (with the STM, power regulator, the two quartz osc) plus a battery protection chip (XB7608AJ)

HW design is getting along nicely, but I've been trying to get the STM32 into a deep sleep mode, as it draws about 30mA on idle right now. Perhaps configure interrupts to timeout after 5s of inactivity on the K line, and wake up when it's pulled down. Can't get it to wake up though. Other issue is just how to kick the STM in sleep mode, as the UART is blocking and I wasn't able to trigger an UART timeout...

Do you have any idea on how I could proceed? I'm not that well versed in libopencm3...