Adding CAN-FD bootloader support as well?

[dgrnbrg]

Hello, I was hoping to ask you a question about how this bootloader works. I have a project that I'd like to be able to program via a USB port as well as over CAN-FD when it's built into a robot. I found your fork of this DFU bootloader which supports the SAMD51--my project uses the SAME51, which I think is identical except for the added CAN-FD hardware. I wanted to see if you think that this structure (essentially polling for CAN & USB alternatingly) would work.

Do you think this is the best way to insert another hardware programming protocol?

Thank you!

[CraigHutchinson]

HI @dgrnbrg . You are correct, the 'E' variant is the same as the 'D' but adds Ethernet And/or CAN. Fundamentally the code does need a good set of clean-up and its very much resolving around USB.

I don't feel you really want to perform both USB+CAN at the same time as that sounds like a recipe for easily bricking a device i.e. If I started DFU on both USB and CAN at the same time, or triggered a USB reset during a FW update etc.
Ideally, I'd think you'd want to have an initial Idle state that that has both busses enabled and then sets the appropriate mode once a connection on either is started. In this manner activity on another bus cannot interfere with the important firmware upload process.:

1. Idle - USB + CAN enabled

• awaiting initial request, enter state 2 or 3 accordingly

2. USB DFU

• CAN disabled
• Returns to Idle on complete

3. CAN DFU

• USB disabled
• Returns to Idle on complete

As CAN is completely out of scope for our work I cannot help there but if You find bugs/issues in the existing code we are happy to assist in those parts as to mutually benefit us both.