Issue Flashing J19 MCU

[james7x1]

We are trying to salvage a J19 MCU from a pybadge board. It accepts and runs the bootloader, but when I attempt to update the firmware to "firmware-pycubedv04_J19.uf2", the board doesn't restart and appear in Windows 10. We are using the pybadge development board currently before transferring the MCU to the Pycubed board.
The current INFO_UF2.txt states:"
UF2 Bootloader v3.13.0-dirty SFHWRO
Model: PyCubed
Board-ID: PYCUBED_J19"

Do you have any suggestions?

[maholli]

Hi @james7x1

It could be a number of things, so let's check some of the basics. Is your PyCubed mainboard a v4 or a v5? (you're attempting to use v4 firmware) What flash chip are you using? No signs of life after leaving the bootloader sounds like it could be an issue with the external flash. After transferring the UF2 (and unplugging/plugging the board back in if need-be), does the RGB LED illuminate at all? If so, what colors?

[james7x1]

Thanks for the quick reply Maholli,
The mainboard that we will transfer to is based on v4. We are currently using a pybadge eval board with the J19 MCU. The peripherals are slightly different but may be compatible.
So far:

1. Double clicked reset, which starts bootloader mode and Windows 10 opens the storage contents
2. Copy-paste "update-bootloader-pycubed-v3.14.0.uf2" from the CircuitPython website
3. The board restarts and opens in the bootloader mode and Windows 10 opens the storage contents
4. I attempt to copy-paste "firmware-pycubedv04_J19.uf2" to the board, but it does not light up LEDs, make, sound, or connect to the computer after at least 2 minutes.
5. I can re-enter bootloader mode by double-clicking the reset button

[maholli]

I see. Well that's why it isn't working. There are specific pins the MCU uses to talk to the external flash chip (which is where it's trying to initialize the file system). Without the proper flash chip on those exact pins, the MCU cannot initialize the filesystem and mount it to your computer. See pic:

You'll need to move the MCU to your pycubed board if you want to program it with the pycubed firmware. You could recompile circuitpython for your pybadge board but that doesn't seem productive. Accessing the bootloader as you have confirms the MCU is working, your next step should be reworking the part onto your board.

Let me know how it goes!
Max

[james7x1]

Thank you so much Max! I will push forward to finish our custom pycubed board so that we can test. I'll update this thread once I attempt firmware installation on-board.
I really appreciate the fourm's help to save my team a lot of debugging time as we are waiting for our custom board to come in.