One of two nRF52840 USB sticks DOA

[Keld_Norman]

I have just purchased 2 pcs. nRF52840 - one of them works fine - the other one reports this when i run dmesg on my linux (tested on 2 different systems) "Cannot enable. Maybe the USB cable is bad?", then it reports "attempt power cycle" and repeats the err. 

Thew stick is connected directly to the USB port

The stick is not damaged in any way and the components looks ok when compared to the other stick.

Best regards

Keld Norman

[Keld_Norman]

yes - tested in a windows10, a fitlet2 running debian and another linux running kali - same message. The first stick worked fine but when i got to the other one i never got it to identify it self so i could upload the f irmware to it. I thought the firmware needed to be loaded before it could identify it self to the system - like a low level driver function ? I have never worked with this nRF52840 before so excuse me my missing knowledge about how it works.

[Andreas]

Hi,

 

No worries, noone is born an expert with any of our products.

 

The dongle should be shipped with a bootloader that allows programming over USB, it might be something to do with that. Could you see what the voltage is on VDD_nRF (test point on the bottom)? This should be 3V. This not being 3V is itself not a problem, but indication that something is up with the bootloader.

Also, if you are able, what is the voltage across C20? This should be 3.3V if the USB part of the IC is powered and running correctly.

 

You might find this blog post handy: https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial

It is probably of little use to solve this problem,but might shed some light on the nRF52840 dongle in general. There is also a description of how to flash the bootloader if that is corrupted.

 

Best regards,

Andreas

[Keld_Norman]

great guide - i will find the voltmeter and measure - thnx