nRF52840 Dongle is Serial Port Library via USB Possible?

[Eric]

Hello,

I am developing an application with SDK 15.2 on my nRF52840 development board (pca10056) and want to run it on my nRF52840 dongle (pca10059). I have hit a problem in porting the program to pca10059 dongle. First I'll explain the application I'm trying to port which is important to the nature of the problem.

My development board application involves using the serial port library and communicating with a linux computer via UART over USB. Messages travel via UARTE1, of which RX and TX are set to the pins which are connected to the USB port internally. Thats RX=8 and TX=6 for the development board. NRF logs are being routed through the other UART which is configured GPIO only (not USB connected).

For the Dongle, I dont see how to route UARTE1 traffic over USB, since it seems there are not GPIO pins which connect internally to USB with the dongle. As in case with the development board. Is there any way I can route UARTE1 messages through the USB port of the dongle?

UARTE1 needs to be routed through USB because I need it to show up as a serial device on the linux computer it talks to.

Any help is much appreciated!

-Eric G 

[Eric]

I got this question answered in a private ticket, might as well share the answer I got here to help others:

Hello Eric,

The nRF52840 DK has a programming chip (The large black chip on the DK with the white sticker with some serial number and board name, PCA10056).

This chip is used for programming the nRF52840, in addition to translate from UART to RS232, which is a USB serial protocol. The segger chip uses the pins 6 and 8. If you use any other pins than these, you will see that you can't see the UART communication through the micro USB port.

The nRF52840 dongle does not have this programming chip, and hence, it will not translate from UART to something that a USB port understands.

Another thing is that the pins\pads that make the USB port on the dongle can not be used for UART. They are hard coded to USB pins, and not PX.YY, which are the pins that can be used for other peripherals. You can see this on the pin assignment for the nRF52840.

Best regards,

Edvin

[Vidar Berg]

Hello Eric,

Can add that the CLI module supports USB CDC as backend so you can use the built-in USB peripheral for logging. Link to CLI example which you can run on the dongle: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.2.0/cli_example.html?cp=4_0_0_4_5_7 

[Eric]

Yes thats the method I chose based on some other posts around here thanks!