Not the OP, but my understanding (admittedly a few years outdated) is that an MSP430 will, in idle, with sleep states properly set up and low power modes in use, drain a coin cell battery (e.g. CR2032) over a period of years - with the current drawn around 1.5 uA in standby and 0.1uA in RAM retention idle.

That is likely even lower than the effective self discharge rate of a lithium coin cell battery. I don't believe the Arm equivalents like the Cortex M0 can deliver such low absolute current - maybe microamps, but more than an MSP430 from what I can see.

Ref - https://metebalci.com/blog/measuring-the-power-consumption-o...