Why can't I write to Program / Boot Flash memory?

If you try to write to Program / Boot Flash Memory on the PIC32MZ and are only able to read back the default bit values (0xFF), your writes to memory were not successful.

Before writing to Program / Boot Flash Memory, you need to unlock it first. This prevents you from accidentally writing to this important memory area. The device has two registers which control the write lock on the memory:

  • NVMPWP: Program flash write-protect register
  • NVMBWP: Flash boot (page) write-protect register

These registers need to be configured by performing the unlock sequence and performing atomic instructions on the registers. Please see the PIC32 Family reference manual (search the device page on Microchip.com) for more information.

© 2018 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.