20.4.3.3 Writing a Code Word

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