Debugger fails connecting to MCU

RE: Debugger fails connecting to MCU

A.P — Tue, 24 Mar 2020 08:25:10 GMT

Found the problem.
One of the Pins in my connector was slightly loose, so it would sit well when trying one board, but won't connect properly on another.

Thank you to everyone who helped!

Closing the ticket.

RE: Debugger fails connecting to MCU

haakonsh — Mon, 23 Mar 2020 12:30:47 GMT

~3V is fine, but given that you have other working boards it indicates an HW issue.

Have you set the APPROTECT in any/all your boards?

I think a logic scope of the SWDIO and CLK lines might possibly show symptoms of some HW issues.

I would also monitor VDD with a high sample rate oscilloscope during a recovery procedure.

Measuring current consumption can also reveal symptoms as currents above 15-20mA indicate an HW issue.

RE: Debugger fails connecting to MCU

A.P — Mon, 23 Mar 2020 10:02:52 GMT

The VDD range is ~3V. But the same exact setup connects to different copies of the same board, so I don't think the setup is the problem here.

RE: Debugger fails connecting to MCU

haakonsh — Mon, 23 Mar 2020 09:49:09 GMT

What's the VDD voltage of the custom board?

The OB J-link only supports 2.8V.

RE: Debugger fails connecting to MCU

Turbo J — Sun, 22 Mar 2020 16:15:47 GMT

If you had trouble with cables, you can try reducing the SWD clock speed.

E.g. using nrfjprog -f NRF52 -c 500 -recover