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

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

haakonsh — Mon, 20 Feb 2023 20:50:36 GMT

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.

[quote user="iz9"]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.[/quote]

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.

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

iz9 — Sat, 18 Feb 2023 14:22:54 GMT

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!

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

haakonsh — Fri, 17 Feb 2023 19:17:08 GMT

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 :/

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

iz9 — Fri, 17 Feb 2023 18:19:54 GMT

The VDD net is simply not powered. As I understand it, one of the modes of operation for this microcontroller is "high voltage mode" where "The system enters High Voltage mode when the supply voltage is only connected to the VDDH pin and the VDD pin is not connected to any voltage supply." (Page 59 of the datasheet v1.3).

I believe my design almost exactly follows the sample layout variation 2, aside from the lack of a connection between DEC4 and DEC6, and the fact that all VDD pins are not externally connected.

[quote userid="13562" url="~/f/nordic-q-a/96770/struggling-to-flash-boot-and-possibly-power-custom-nrf52833-qdaa-hardware/410715"]You also need to know that you will break the GPIO spec if you connect any GPIO to a power supply when VDD is unpowered.[/quote]

Understood. I did provide power through my 10k pull-ups for I2C initially. I'll ensure those remain unpopulated moving forward.

At present, I only have the sections of schematic labeled "NRF52833 MCU", "Resonator", "RF", and "Power Filtering" populated. In essence, just the components provided by the reference layout and schematic.

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

haakonsh — Fri, 17 Feb 2023 18:07:10 GMT

[quote user="iz9"]I do have access to an NRF52832-DK if that helps.[/quote]

Hmm, maybe, I'm not sure, you'll just have to try. The on-board debugger can attach to external targets via P19 or P20.

[quote user="iz9"]Which pins would be the JTAG pins on the QFN-40 version of the package (NRF52833-QDAA)? It was my understanding that those are only exposed on the aQFN and WCLSP packages.[/quote]

The SWD interface is present on all programmable nRF devices, through the SWDIO and SWDCLK pins.

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

haakonsh — Fri, 17 Feb 2023 18:01:40 GMT

I've checked your design files and I struggle to understand how the VDD net is powered. It seems that the VDD vias are not connected to a power supply, or anything else for that matter.

You also need to know that you will break the GPIO spec if you connect any GPIO to a power supply when VDD is unpowered. As a result current will flow through the GPIO's ESD diodes and into the VDD net, thereby powering the device. These ESD diodes are not spec'ed to handle any current at all and will fail in an unpredictable manner, causing a near infinite set of issues. One of which could be the one you're describing.

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

iz9 — Fri, 17 Feb 2023 17:53:13 GMT

I unfortunately don't have access to a J-link. I do have access to an NRF52832-DK if that helps.

Which pins would be the JTAG pins on the QFN-40 version of the package (NRF52833-QDAA)? It was my understanding that those are only exposed on the aQFN and WCLSP packages.

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

haakonsh — Fri, 17 Feb 2023 17:39:57 GMT

Are you able to connect to it with a J-link and nrfjprog?