Sleep on SAMD21 only working after restart?

[maxholgasson]

Hello,
I was now seachring for hours why my SAMD21 won't sleep after I found out that after programming I had to restart the chip.
It works this way but why and how?

Working with the AVRs like 328P I had no issues like that

[Jackjan4]

@maxholgasson Do you put it in standby or idle?
( LowPower.standby() vs LowPower.idle(...) )

[maxholgasson]

HI, I'm using standby

[rocketscream]

It works just fine over here as we test every piece of our SAMD21 based board during production that way.