Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Atmel/AT91SAM9G10/PMC/CKGR_PLLAR#0x0
PLL A Register
Divider A
PLL A Counter
PLL A Clock Frequency Range
PLL A Multiplier
https://github.com/cmsis-svd/cmsis-svd-data