nRF52840 dongle usb cdc acm

[Joseph91]

Hello I am trying to get the usb cdc acm module to work for the nRF52840 dongle.  However, the example is made for the dev kit.  I flashed the dongle with the example anyways and nothing happened.  I have attempted to configure it to the dongle but to no avail.  Can someone point me in the right direction on how to figure out what to change in the example to get it working on the dongle? Thanks!

[Vidar Berg]

Hello,

I made a 'pca10059' configuration of the peripheral usbd_cdc_acm example for the dongle, please see attached. The main difference compared to the original "DK" configuration is that this one does not overlap with the pre-programmed MBR section (address 0x0 - 0x1000 in flash and 0x20000000 - 0x20000008 in RAM).

The MBR section is required for the DFU support as Einar explains here: https://devzone.nordicsemi.com/guides/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial 

USB CDC ADC project for the nrf52840 dongle

nRF5_SDK17.1.0_usbd_cdc_acm.zip

Best regards,

Vidar

[Joseph91]

Thank you so much for the help.  However, I was under the impression that using usb cdc acm would create a virtual com port that would be identifiable.  When I flashed the dongle, no com port was created.  The dongle shows up as com port 11 when first connected, but that port is no longer available once flashed.  My end goal is to have a python script running with pyserial that will receive the data sent by the dongle.  However, I need to specify which com port is associated with the dongle for the python script to receive.

[Joseph91]

Sorry, you can disregard that last message. It was a mistake on my end, and I resolved the com port issue.  Thanks again!

[Joseph91]

Hello again Vidar. I had another question for you.  With your help I was able to successfully get the dongle to write the data I wanted over serial.  However, I am having trouble using the read function.  I know it returns NRF_SUCCESS or PENDING depending on the status.  So I am a little confused on how to actually retrieve the data being the read.  I have tried to access the data from the buffer pointer, but that hasnt worked either.  Thanks for any help.

[Vidar Berg]

Hello,

The data is retrieved through the app_usbd_cdc_acm_read() function. In the example, the received data is just being copied into the 'm_rx_buffer' variable, but you can change this to make it copy the data to some other buffer if you want. Another example of this is the USB ACM event handler in the USBD BLE UART Example project which fills up an application buffer to be transmitted over BLE.