MartinL:
Hi farlane,I ran a small test. It looks like a read of the PER register returns the last value written to it, but like you mention it's not updated directly from the PERB register during double buffering, as described in the SAMD21 datasheet.
This suggests to me that perhaps internally the period double buffering isn't actually using the PER register.
Looks like another "undocumented feature" in the SAMD21 datasheet.
Hi Martin, thanks for your time and troubles double checking this. A very strange behavior indeed given that the CC[X] registers are in fact updated with their buffered counterparts ...
Cudos & thanks again 