20.4.3.5 Writing a Configuration Word

The algorithm for writing a Configuration word is as follows:
  1. Write the 0x1D (WORD_WRITE) to the NVMCMD register
  2. Write the low byte of the data to the low byte of a configuration word location
  3. Write the high byte of the data to the high byte of the same configuration word location. This will start the Flash write operation.
  4. Wait until the NVMBSY bit has been cleared