USB and serial enabled LCD backpack firmware updates

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The LCD backpack can be upgraded over the USB connection. It uses a modified version of the Diolan USB PIC bootloader. This bootloader, written in ASM and released under the GPL, enumerates as an HID device. The bootloader app is included in the project archive.

A neat thing about the LCD backpack firmware is that it can be loaded with a normal programmer too. The firmware has a jump instruction at the appropriate location so that if a bootloader isn't present it will still work.

Follow these instructions to bootload a new firmware into the LCD backpack.


Stuff you'll need

Step 1. Activate the bootloader with a jumper on PGC/PGD

PIC LCD backpack.png

Follow these steps to enter the update mode:

  1. Place a jumper between the PGC and PGD pins
  2. Plug in the LCD backpack
  3. The backpack connects as a USB HID device
The LCD backpack bootloader is a USB HID device, not a serial port.
No serial port will be added to your system!!!

Step 2. Upload the firmware

Download the latest firmware update package.



The Windows updater is included in the upgrade package, just run the .bat file corresponding to the firmware version you want to load.

You can safely ignore any warnings about the EEPROM and ID, these ranges are not included in every firmware update.

Command line: Windows, Linux, OSX, BSD

Bootloader applications are also available for BSD, GNU/Linux, and Mac.

fw_update -e -w -m flash -vid 0x04D8 -pid 0xFA98 -ix HD44780LCDv1-firmware-v1.0.hex

The basic command line parameters are shown above.

  • -e (erase)
  • -w (write)
  • -v (verify)
  • -m all (all memory, could be changed to flash)
  • -vid 0x04D8 -pid 0xFD0B (the LCD backpack bootloader USB IDs)
  • -ix HD44780LCDv1-firmware-v1.0.hex (the input firmware file, HEX format)

Step 3. Reset the LCD backpack

Unplug the LCD backpack, remove any jumper, and plug it back in. The upgrade is complete.