Migrating an older product from S110 to S130 and I'm having trouble with power consumption in sd_power_system_off

RE: Migrating an older product from S110 to S130 and I'm having trouble with power consumption in sd_power_system_off

Glen M — Thu, 24 Mar 2022 07:11:39 GMT

I'm going to mark this as solved - I think my issue was primarily related to not getting some hardware on the board properly shut down, plus difficulty measuring due to a supercap on the board.

I did learn one valuable thing from this - it's well documented but it just didn't sink in when I first developed this firmware: you don't come back where you left off with sd_power_system_off. When you "wake up" from that, it's a reset event. I had unnecessary code in there trying to set up my peripherals again when I detected a wakeup.

Thanks!

RE: Migrating an older product from S110 to S130 and I'm having trouble with power consumption in sd_power_system_off

Kenneth — Wed, 23 Mar 2022 12:57:19 GMT

I don't remember the system OFF current in the back of my head, but it's typically sub 1uA. So if you are measuring more than this, then it is likely a GPIO that is either floating with undefined input level, or sinking or sourcing current through a output pin. If it's the first you should see a change in current by simply moving the finger over the chip and components and/or just poke with a 1Mohm resistor to ground around the pins to see which is the likely culpit.

Kenneth