XIAO BLE Sense in deep sleep mode

[AdamM68]

Getting lower power consumption on Seeed XIAO nRF52840

I found good hints on this topic page XIAO BLE Sense in deep sleep mode. But many of the code snippets I saw in the thread were not working as I expected. I dug into the arduino core try to understand the underlying implementation. Based on my digging, I developed the below sketch. The arduino loop runs at 3uA (with a major caveat). It demonstrates system_off sleep with wake up on gpio interrupt, system_on sleep, and a low latency Arduino main loop. More info on my findings below the sketch. (I …