This sketch will allow you to update the bootloader on your chipKIT board. It comes bundled with a number of common board's bootloaders, but if your board doesn't have the bootloader bundled you can upload the .HEX file for the bootloader to the board through serial.

This is a fully command-line driven system where you type in commands to make it do thing.

It also has the ability to change the USERID in the DEVCFG3 config register, which is available for use as a USB serial number on some boards.

• CLI library: https://github.com/MajenkoLibraries/CLI

PIC32MX1xx/2xx

Clock switching is required to be enabled in the existing bootloader.

There are some issues programming the top page of boot flash since that is where the config bits are. Erasing that page can crash the whole chip. To counter this the clock source is switched prior to writing the last page of flash to the FRC+FRCDIV clock source. Because of this the USB communications will be disabled at this point and cannot be re-enabled. It is impossible to switch back to the normal clock source after writing the last page.

If clock switching is disabled the CPU will stall when the config bits are erased and writing the new config bits will not be possible, leaving the chip in an unconfigured state. The bootloader will only be part programmed and unable to execute. The only recovery method is to write the bootloader using a hardware programmer such as a PICkit3™.

USB

It is recommended that you use an external USB to TTL Serial adapter and communicate using the normal UART pins of your board instead of the USB port for pure-USB devices (that is devices that lack an FT232 chip as a USB interface).

The UART is configured for 9600 8-N-1 operation.

Commands:
  help              This screen.
  load <source>     Load bootloader from <source>
       internal     Load internally bundled bootloader
       ascii        Receive a plain text HEX file as ASCII
  info              Display current state information
  burn              Burn the loaded bootloader
  dump              Dump the bootloader to the screen
  userid <uid>      Set the board's UUID
  reboot            Reboot the board

This software comes with no warranty whatsoever. Use of it is entirely at the user's own risk. Majenko Technologies, chipKIT, nor any of its associates, members or partners, can be held responsible for problems arising from the use of this software.