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Using an Atmel JTAG ICE with SWD

Posted: Fri Feb 24, 2023 8:45 pm
by jpelletier
We're currently using an Atmel/Microchip JTAG ICE to program our NetBurners (MODM7AE70).
We simply removed the resistors going from the ATSAMD20E to the ATSAME70 (R16, R22, R23, R24) and connected the programmer on the SAME side.

For Netburners v1.4, this works fine. For more recent ones (v1.5), this no longer works. What changed between these 2 versions and can we make this work with v1.5?

Re: Using an Atmel JTAG ICE with SWD

Posted: Tue Mar 07, 2023 4:37 am
by jpelletier
We solved the issue by wiping the flash clear, since it seemed the firmware was either locked (fuses) or prevented modifying the flash (possibly overwriting the bootloader). This of course, made the web interface unavailable.
We found that by leaving the resistors on board (R16, R22, R23, R24) and holding the SAMD20 in reset allows access to programmation and debugging of the chip with the SWD interface. The application can then run even if the SAMD20 reset is released.