UART is corrupted on central side while its virtual COM on DK looks fine

[Amin]

I am working on a project using UART service to send data between two stations. First board is a logger which has a nRF52840 connected to  a serial and when it powers up sends about 2KB of data via BLE to the central board. When I program nRF52840-DK with the central UART and check its VCOM terminal all data are received perfectly, but when I program my custom board the last data are corrupted and can not be received perfectly. So my question is about VCOM serial. Is it a mirror of physical uart0 of DK?

[Sigurd Hellesvik]

Hi,

Is it a mirror of physical uart0 of DK?

Read more about the VCOM at nRF52840DK -> Virtual COM port.

Which pins do you use for UART on the custom board? (Some are not recommended for high frequency)

The nRF52840DK UART pins (which are also forwarded to the VCOM) is actually available on DK pin headers.
This gives you two options for testing here:

1. Connect your external UART reader to the DKs UART directly. See nRF52840DK -> Virtual COM port for pins.
2. If you erase the code on the nRF52840, you can connect your custom board to the same pins, and you should be able to see the UART from the custom board through the DKs VCOM.

Regards,
Sigurd Hellesvik

[Amin]

Thanks Siguard

P0.13 is Tx and P0.24 is Rx on my custom board (E73-2G4M08S1C).

Sigurd Hellesvik said:

connect your custom board to the same pins, and you should be able to see the UART from the custom board through the DKs VCOM

I connected Tx pin to P0.06 of DK them as you said above. The output was the same as before. 

Then I modified dts file of nrf52840-DK and changed Rx and Tx pins to be 0.13 and 0.24 as mine and see those pins are OK on Dk board (0.13 and 0.06 were shorted to see COM0 output). I programmed my custom baord with this Dk code and it works fine now.

I guess the dts file had some bugs in it.