28.8.3 Performing a Page Write

To execute page write, set up the address in the Z-pointer, write “X0000101” to SPMCR and execute SPM within four clock cycles after writing SPMCR. The data in R1 and R0 is ignored. The page address must be written to PCPAGE. Other bits in the Z-pointer must be written to zero during this operation.

  • Page Write to the RWW section: The NRWW section can be read during the Page Write
  • Page Write to the NRWW section: The CPU is halted during the operation
Note: If an interrupt occurs in the timed sequence the four cycle access cannot be guaranteed. In order to ensure atomic operation disable interrupts before writing to SPMCR.