USBD starting up lowers board's overall current draw

RE: USBD starting up lowers board's overall current draw

Jared — Mon, 27 Jun 2022 14:18:54 GMT

To be honest, it difficult to be sure whether this is a SW or a HW issue without knowing whether it's reproducible on a DK or not. Did you try to enable the log, did it say anything useful?

RE: USBD starting up lowers board's overall current draw

Kraig — Tue, 21 Jun 2022 15:51:01 GMT

[quote userid="73165" url="~/f/nordic-q-a/88594/usbd-starting-up-lowers-board-s-overall-current-draw/373487"]Meaning the logger with RTT as backend? Is NRF_LOG_ENABLED = 1?[/quote]

No, NRF_LOG_ENABLED = 0 and NRF_LOG_BACKEND_RTT_ENABLED = 0. Maybe I'll turn that on and see if it spits out any good info. Thanks.

[quote userid="73165" url="~/f/nordic-q-a/88594/usbd-starting-up-lowers-board-s-overall-current-draw/373487"]Does a power-on reset affect the current consumption in any way? [/quote]

Regardless of how it starts, if USB is connected and the USBD module starts, the power is lower than if it starts without USBD. And it is that constant draw that appears to be the only change, which is why I think it is some pin configuration or some peripheral turned on.

Thanks for the questions.

RE: USBD starting up lowers board's overall current draw

Jared — Tue, 21 Jun 2022 14:02:02 GMT

[quote user="Kraig"]There is no other code that uses the USBD module. We don't use the Logger module. We do use the Segger RTT print statements, but that code is ifdef'd out.[/quote]

Meaning the logger with RTT as backend? Is NRF_LOG_ENABLED = 1?

[quote user="Kraig"]Yes, we have quite a few samples showing this, but if we re-flash the entire chip, the problem goes away. I haven't nailed down the procedure to make a sample start doing it.[/quote]

ok, so it's essentially the same as what the other user in this thread described.

Does a power-on reset affect the current consumption in any way?

regards

Jared

RE: USBD starting up lowers board's overall current draw

Kraig — Tue, 21 Jun 2022 01:05:39 GMT

There is no other code that uses the USBD module. We don't use the Logger module. We do use the Segger RTT print statements, but that code is ifdef'd out.

Yes, we have quite a few samples showing this, but if we re-flash the entire chip, the problem goes away. I haven't nailed down the procedure to make a sample start doing it.

I was thinking the same as your guess. Because it is a rise in the steady current draw, I was thinking some pin is configured bad for the circuitry, causing a current leak. I did see that the lower USBD driver had calls to disable pull-ups, but calling that directly didn't make a difference. I also tried to directly call start/stop functions with no luck either, hoping they would disable interrupts or other pin assignments. Not sure if I can call those directly. I am just trying random stuff now.

RE: USBD starting up lowers board's overall current draw

Jared — Mon, 20 Jun 2022 13:10:52 GMT

My guess is that something else is being indirectly affected when you comment out the USBD part. Is there any other code part that depends on that module? Are you using the logger, if so what backend? Have you reproduced this on multiple samples?

RE: USBD starting up lowers board's overall current draw

Kraig — Tue, 14 Jun 2022 19:05:05 GMT

Sorry for the delay in my response. There could very well be another reason unrelated to the USBD. It is because I can repeatably get a difference in the current draw depending if I let the USBD start up or not that I was focusing on it.

Unfortunately because the code base runs on our custom board with different pin assignments and chips than what is on the DK board, it would be a significant amount of modifications to make it run on the DK. I don't think the code would be anywhere near representative, so I don't think it would be worth the effort at the moment.

RE: USBD starting up lowers board's overall current draw

mark.blackburn.orpyx — Wed, 08 Jun 2022 16:06:19 GMT

Something else about this high current draw problem: Reflashing the processor with the same code resolves the problem.

I was troubleshooting a unit that had the same problem Kraig described. I saved the image using the nRF Connect programmer, than loaded an image onto it which resolved the issue. I then reloaded the saved image onto it expecting the problem to reappear but it didn't reappear.

Is there any non-volatile state in the nRF52840 that would not get saved in the image file when using nRF Connect Programmer. To narrow it down any state that could affect GPIO configuration?

Also, loading firmware via the DFU bootloader does not resolve the problem. Only flashing it seems to resolve the problem.

RE: USBD starting up lowers board's overall current draw

Jared — Tue, 07 Jun 2022 13:57:21 GMT

Hi,

I can't say that I've seen this before. Maybe something else in your code is effected when you comment out the USBD part. Have you tried flashing a development kit with your project? Do you measure the same with the dk?

regards

Jared