Failed to power up DAP Cannot connect to targe

RE: Failed to power up DAP Cannot connect to targe

Hung Bui — Wed, 26 Oct 2022 11:34:09 GMT

Ok so my understanding is that you only got into this issue after you flashed a firmware (bootloader?) to the chip ?
There could be a chance that if there is a firmware that trigger reset too early in the code it may block the debugger from accessing the chip.

But it's pretty small chance that you have such firmware.
So I'm not so sure if it was because of the firmware you flashed on the board that blocking the debugger or it's something else was wrong with the chip, possibly with the hardware.

No there is no way to erase the chip without the debugger.

RE: Failed to power up DAP Cannot connect to targe

dgibson2 — Wed, 26 Oct 2022 10:44:43 GMT

Hi,

That's what I thought, the chip is powered properly, our board has a number of testpoints and all are at the expected values.

Unfortunately it seems as though it may be a lost cause as I am unable to connect via JLink, I was hoping there was a way possibly to flash it without a connection however I understood that it was unlikely,

I had attempted both nrfjprog --eraseall and erasing through JLink to no avail.

Thanks anyway

RE: Failed to power up DAP Cannot connect to targe

Hung Bui — Wed, 26 Oct 2022 10:35:00 GMT

Hi Darren,
If you connect the nordic dongle to a SWD interface you can erase the whole chip the same way as you do with a Dev Kit.
You can either use nrfjprog --eraseall or you can use Jlink Commander to do that.
But from what I can see in the log is that the Jlink was not able to connect to the chip hence can't do anything with it.
Please double check if you have powered the chip properly and if you have all the pins for SWD connected correctly.

RE: Failed to power up DAP Cannot connect to targe

dgibson2 — Wed, 26 Oct 2022 09:31:34 GMT

Hi,

The device has an SWD interface however it isn't working right now, the jlink itself has a steady orange light when connected to the problemed board. I know this problem doesn't lie with my Jlink ultra as I was able to use it to program another one of the boards we have.

The setup we're using is essentially a nordic dongle with an SWD header attached, they're functionally near identical as it is being used to replace a dongle in our systems.

The reason that I required a bootloader to be added is because we were adding an assembled zip file via nrfutil to program the chip, this is not my problem anymore as this aspect is working fine and up to our requirements.

The problem lies solely with the board that I had been working with initially and I believe I may have bricked it/corrupted the memory. Would you know if there is any easy way to wipe a nordic dongle? As this would function just as well on our custom board.

RE: Failed to power up DAP Cannot connect to targe

Hung Bui — Wed, 26 Oct 2022 09:16:22 GMT

Hi Gibson,

If you have access to the SWD interface of the chip, I don't see much point to have a bootloader on the dongle.
You can just directly write to the flash of the nRF52840 without using the bootloader.

Of course if you want to only use the dongle with USB and don't have to connect to a debugger then a bootloader would be useful.

What I would suggest to test is to try read and write to flash before you test with writing the bootloader. Just try testing if you can use nrfjprog or Jlink commander to read the flash, erase and write. Just to be sure the SWD interface is correctly working.

Could you send a photo of your set-up ?