SAMD51 Thing Plus C and SWD programming

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1

I seem stuck trying to load a custom bootloader via a J-Link Edu interface using SWD. I routinely reprogram SAMD21 projects using Segger’s J-Link Edu and Microchip Studio. When I first tried this on the SAMD51 Thing Plus, it warned me that the Security Bit was set and that clearing the bit would clear the Flash memory. I let it do that.

Now when I try to read the CPU ID I get: “Error connecting to device over SWD Unable to enter programming mode. Verify device selection, interface settings, target power, security bit, and connections to the target device.”

Why would the Security Bit be set on these products? Is anyone successfully reprogramming them via the SWD interface?

2

Hello @rrainey. I did my best to recreate what you’re going through but unfortunately I don’t have a J-LInk EDU so with that said, I was able to program my SAMD51 Thing Plus with an ATMEL-ICE using Microchip Studio over SWD. I was not getting a “security bit” error or warning when I went through the process. It’s possible that it’s a J-Link issue and I wish I had one to try to reproduce the error. Have you had any luck in the mean time?