Struggling to flash, boot, and possibly power custom NRF52833-QDAA hardware

[iz9]

Hi there. I've designed a PCB around the NRF52833-QDAA, mostly following the variation 2 sample layout. Upon assembling my board, I was able to flash it exactly one time using an STLink and SWD (to a blank PlatformIO zephyr project). Ever since, I've been unable to get the NRF to show up as a target using either the STLink or a blackmagic probe. I did not connect all VDD Pins together and I failed to connect DC4 and DC6, but manually connecting those with wires hasn't seemed to make a difference in current draw or connection status. My current draw is presently ~420uA when powering the device with 3v3 to the VDD pins. This feels too low to me, as I was expecting around 3mA for active CPU mode. I get approximately the same current draw when providing 5v to VDDH.

I ultimately plan to power this in high voltage mode, which as far as I understand, means I only need to provide a voltage of 2.5-5.5v to the VDDH pin. Is my understanding correct, or is there some necessary configuration in order to use High voltage mode? It was my also my understanding that was automatic.

I've uploaded my KiCad board files to github for possible review. Any feedback or information you may be able to provide me with is much appreciated.

Thanks!

[haakonsh]

Only REG1 is powered internally by REG0. That means that the internal 1.3V power rail is powered, but the rest of the device is not. 
I believe pin 8 is connected to the output of REG0 and this VDD pin is used to power the rest of the VDD net externally. 

And yes, this information should have been added to the PCB guidelines or the regulator chapter in the prod spec :/

[iz9]

I replaced the old Microcontroller with a brand new one, and the board immediately appears to function. My blackmagic probe immediately detects the target.

I'm a little hesitant to just attempt to flash this however, and am curious if you can provide a little more information on board configuration and setup. Within the NRF Connect SDK, I only see an option to create custom hardware using the aQFN (QIAA) version of this package.

As far as I understand, all packages contain identical silicon, simply with more or less pins exposed. Is it safe to create a program around the QIAA, and flash it to the QDAA? Or is there some special configuration I need to perform?

Thanks!

[haakonsh]

All variants of the nRF52833 has the exact same design, but you will have to note that some gpios are ofc not available on the QDAA variant. If you base the the board of the QIAA/nRF52833DK be aware of any 'default' pins in the QIAA devicetree. I.e. uart0 might have assigned gpios that are not available to the QDAA variant. You just need to double-check en change any such configuration.

iz9 said:

I'm a little hesitant to just attempt to flash this however, and am curious if you can provide a little more information on board configuration and setup. Within the NRF Connect SDK, I only see an option to create custom hardware using the aQFN (QIAA) version of this package.

Note that you are still operating the device out of spec and you will likely experience issues in the near future. If you connect the VDD vias with wires you might be able to mitigate a few of the impending issues.

You are kinda on your own here, we can't help you debug any issues as long as you're running off a faulty power supply.