XIAO SAMD21 register to set exception_table

Products & Technology XIAO
1

Hello to Seeed tech team.

Super technical question, I can’t find the answer with the SAMD21 datasheet.
The bootloader code I found is in binary format, so I can’t find the answer there as well.

There is the “exception_table” with ISRs that is located on the first address after the bootloader (0x2000).
Is there a register in the microcontroller that the bootloader is setting to let it know the location of the ISR table? What’s the name? Address?

I want to create a dual boot in the XIAO memory and need to change the location of the ISR table.
How can I do that?

Can I get the bootloader code for the XIAO SAMD21 please?
It will be much easier to implement the dual boot mode right in the bootloader…

Thanks!

2

Hi there 4projct,

Obtain the bootloader binary from the Seeed GitHub
 here: https://github.com/Seeed-Studio/ArduinoCore-samd/tree/master/bootloaders/XIAOM0.
It recommends (and I used) the non-update file: 
bootloader-XIAO_m0-v3.7.0-33-g90ff611-dirty.bin which has to be downloaded “raw” and saved to the convenient directory.

That’s the link from this how to unbrick HTH
GL :slight_smile:
PJ

3

Thanks.
But I need the real bootloader code to understand what they do there…

But I think I found what I need in other code.
Arduino’s Zero board is also based on SAMD21 and it’s bootloader is public: