Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Atmel/AT91SAM9G25/SHDWC/MR#0x0
Shutdown Mode Register
Wake-up Mode 0
Counter on Wake-up 0
Real-time Clock Wake-up Enable
https://github.com/cmsis-svd/cmsis-svd-data