Modification of the usb_cdc_acm example for custom nRF52833 board and integrating with usb_hid

[Sid_mbed]

I have a custom nRF52833 board that acts as an HID device, which works perfectly. I now need to get values from the USB to the serial monitor for easy debugging purposes. I learnt that this could be done using the usb_cdc_acm class.

1. While an example for nRF52840 is given in the nRF SDK, I don't know how to modify it for my custom board in Segger embedded studio in which the code for USB acting as an HID device is written. I tried using  Developing for nRF52811 user guide given in nordic infocenter as a reference but couldn't understand it.

2. I also have no idea how to integrate it with the already existing project in which the USB acts as an HID device.

I am using nRF5_SDK_17.0.2 with Windows 10 OS.

I am a beginner with nRF. Could somebody please help me out?

[Karl Ylvisaker]

Hello,

Thank you for your patience with this.

I am a beginner with nRF.

Welcome!
Please do not hesitate to ask if you should encounter any issues or questions - we're happy to help!

1. While an example for nRF52840 is given in the nRF SDK, I don't know how to modify it for my custom board in Segger embedded studio in which the code for USB acting as an HID device is written. I tried using  Developing for nRF52811 user guide given in nordic infocenter as a reference but couldn't understand it.

When adapting an example to your custom board you will need to make a new board file or description that matches the custom board's layout, since all the examples assumes the different DK layouts. You could take a look in the sdk\components\boards directory to see how these should look.

2. I also have no idea how to integrate it with the already existing project in which the USB acts as an HID device.

Do I understand you correctly that the custom board you have is already using the USB peripheral of the nRF52833?
Please note that the nRF52833 has only got 1 USB instance so if this is already in use by your application we might have to look for other possibilities for these debug messages.

I tried using  Developing for nRF52811 user guide given in nordic infocenter as a reference but couldn't understand it.

Lastly, could I ask you whether there is a particular reason for using the user guide for a different SoC? Is there a specific part of this user guide that you think could be useful, or some other reason?

Best regards,
Karl

[Sid_mbed]

Karl Ylvisaker said:

Do I understand you correctly that the custom board you have is already using the USB peripheral of the nRF52833?
Please note that the nRF52833 has only got 1 USB instance so if this is already in use by your application we might have to look for other possibilities for these debug messages.

Yes, the usb peripheral is already being used as a hid device as a mouse. Is there any way to send data from the nrf module to the computer? I need this as I will require messages to be printed on the computer for troubleshooting purposes.

Karl Ylvisaker said:

Lastly, could I ask you whether there is a particular reason for using the user guide for a different SoC? Is there a specific part of this user guide that you think could be useful, or some other reason?

I had searched the devzone for modifying the usb_cdc_acm example for nrf52833 and had found this: https://devzone.nordicsemi.com/f/nordic-q-a/74407/can-i-modify-source-code-for-the-vitual-com-of-nrf52833-usb-cdc-acm-in-examples-peripheral-usbd_cdc_acm. It was mentioned here that this could be done similar to nrf52811.

[Karl Ylvisaker]

Sid_mbed said:

Yes, the usb peripheral is already being used as a hid device as a mouse. Is there any way to send data from the nrf module to the computer? I need this as I will require messages to be printed on the computer for troubleshooting purposes.

I suppose it should be possible to register a virtual com port (CDC ACM) on the same instance, but for simplicity (and to reduce the chance of meddling in the existing code) I would instead recommend that you make use of UART or RTT for the debugging messages, if possible.
Could this be an option?

Sid_mbed said:

I had searched the devzone for modifying the usb_cdc_acm example for nrf52833 and had found this: https://devzone.nordicsemi.com/f/nordic-q-a/74407/can-i-modify-source-code-for-the-vitual-com-of-nrf52833-usb-cdc-acm-in-examples-peripheral-usbd_cdc_acm. It was mentioned here that this could be done similar to nrf52811.

Oh, right - yes, this is correct. The process is very similar, as mentioned by my colleague Simon in his replies.

Best regards,
Karl