Renesas M16C/50 Series User Manual page 798

M16C/5L Group, M16C/56 Group
28.3 Notes on Protection
After setting the PRC2 bit to 1 (write enabled), by writing to a given SFR, the PRC2 bit becomes 0 (write
disabled). Change the registers protected by the PRC2 bit in the next instruction after setting the PRC2 bit
to 1. Make sure there are no interrupts or DMA transfers between the instruction that sets the PRC2 bit to
1 and the next instruction.
R01UH0127EJ0110 Rev.1.10
Sep 01, 2011
28. Usage Notes
Page 761 of 803