1.6.3 USB Device HID Bootloader Configurations

Bootloader Specific User Configurations

For Basic Bootloader:

For Live Update Bootloader:

  • Bootloader NVM Memory Used:

    • Specifies the memory peripheral used by bootloader to perform Flash operations
    • The name of the peripheral will vary from device to device

  • Bootloader Size (Bytes):

    • Specifies the maximum size of Flash required by the bootloader
    • This size is calculated based on Bootloader type and Memory used
    • This size will vary from device to device and should always be aligned to device erase unit size

  • Enable Bootloader Trigger From Firmware (Basic mode only):

    • This Option can be used to Force Trigger bootloader from application firmware after a soft reset. It does so by reserving the specified number of bytes in SRAM from the start of the RAM. The reserved memory is updated by the application with a pre-defined pattern. The bootloader firmware in the bootloader_Trigger() routine, can check the reserved memory for the pre-defined pattern and enter Bootloader mode if the pattern matches.

    • Number Of Bytes To Reserve From Start Of RAM:

      • This option adds the provided offset to RAM Start address in bootloader linker script.
      • Application firmware can store some pattern in the reserved bytes region from RAM start for bootloader to check at reset in bootloader_Trigger() function

  • Use Dual Bank For Live Update:

    • Used to configure bootloader library to use Inactive bank of the device to upload the new application

    • This option is visible only for devices supporting Dual Flash banks

    • Live Update Flash Bank Size (Bytes):

      • Specifies the size of bank in which both the bootloader and application code reside. This value by default will be half of the available Flash memory

    • Trigger Reset After Update:

      • This option can be used to trigger a Swap bank and reset immediately after programming the application in inactive bank
      • If not enabled, then the application code should call the bootloader_SwapAndReset() function to trigger Swap bank and reset

USB Device HID Driver Configurations

  • Vendor ID: 0x04D8
  • Product Id Selection: usb_device_hid_bootloader
  • Product ID: 0x003C
    • To be used to configure Unified Host Application
  • Product String Selection: USB HID Bootloader

Bootloader System Configurations (Basic mode only)

  • Application Start Address (Hex):
    • Start address of the application which will programmed by bootloader
    • This value is filled by bootloader when its loaded which is equal to the bootloader size. It can be modified as per user need.
    • This value will be used by bootloader to jump to application at device reset

Bootloader Linker Pre Processor Macros for Cortex-M Based MCUs

  • Based on the configurations the above linker pre processor macros will be generated in MPLAB X xc32-ld settings
    • ROM_LENGTH specifies the size of the bootloader

Basic mode:

Live Update mode: