Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Atmel/ATSAM3S1C/PWM/CMPM0#0x0
PWM Comparison 0 Mode Register
Comparison x Enable
Comparison x Trigger
Comparison x Period
Comparison x Period Counter
Comparison x Update Period
Comparison x Update Period Counter
https://github.com/cmsis-svd/cmsis-svd-data