Programing NXP LPC via USB as a flash disk (USB ISP MSC)

maxgerhardt · July 19, 2021, 12:30pm

Without doubt, that is the checksum missing from the image.

ARMmbed/mbed-os/blob/d147abc3e556c58e5e343d34b729bc2192e18bd3/tools/targets/LPC.py#L30-L38


      
          def patch(bin_path):
              with open(bin_path, 'r+b') as bin:
                  # Read entries 0 through 6 (Little Endian 32bits words)
                  vector = [unpack('<I', bin.read(4))[0] for _ in range(7)]
          
                  # location 7 (offset 0x1C in the vector table) should contain the 2's
                  # complement of the check-sum of table entries 0 through 6
                  bin.seek(0x1C)
                  bin.write(pack('<I', (~sum(vector) + 1) & 0xFFFFFFFF))

LPC microcontrollers have an additional checksum in the binary over the first 7 entries of the vector table. That was e.g. discussed in LPC 1768 Flashing and Debugging - #5 by valeros.

You can also extend PlatformIO with this logic. For that, add to the platformio.ini the line

extra_scripts = extra_script.py

and then in the root of the project, create a extra_script.py file with the content from lpc1768_blinky_example/extra_script.py at fe34b7b44271502b961fa4e79e1bb30180092133 · jxsl13/lpc1768_blinky_example · GitHub

But comment out all lines after # fix openocd target because that’ll re-target the upload method to OpenOCD, which you probably don’t want.

In PlatofrmIO you can also say

upload_protocol = mbed

and that is basically uploading the .bin file to the available USB disk (as for all mbed-enabled CMSIS-DAP boards)

I’ll open an issue about this, LPC11U35 does not work well? · Issue #6 · platformio/platform-nxplpc · GitHub was closed prematurely without the right fix.