Test UART using GPIO

[Sridhar Jonnavittula]

Hi,

I want to test UART peripheral on nrf52840 by running example in path examples\peripheral\uart as it is.

Connection setup is:

nRF power source USB

nRF USB port connection

Default switch mode

Windows PC having USB to RS232 serial cable enumerating a COM port which its TX and RX pins connected to P0.06 GPIO TX pin, P0.08 RX GPIO pin on nrf52840 PDK

So while testing, most of the times some junk values are coming.

How to resolve this issue?

[cbd]

Hi,

Just to check:

1. Did you connect the ground wire from your USB-RS232 lead to a ground on the board?
2. Did you connect TX to RX on the lead to the board and vice versa?
3. Did you configure both ports for the same settings e.g. board rate, stop bits, parity, flow control etc?
4. Finally does the USB-RS232 lead give a 3.3V or a 5V output, you'll need 3.3V.

[Sridhar Jonnavittula]

1. I did not connect USB-RS232 ground pin 5 to any of GND pin on nrf52840 DK

2. Yes

3. 

and example application don't have Data and Stop bits. Where to set those values?

4. Yes

Is it OK to connect micro USB cable to USB J3 on nrf52840 DK for this test case?

[Marjeris Romero]

Hi,

Which version of the SDK are you using? Have you checked the information in the infocenter for which settings you need to use to test the example? For instance for the newest SDK you should take a look at this page.

Regards,

Marjeris

[Sridhar Jonnavittula]

Yes. I have used latest SDK V15.0.0 only and kept same settings for COM port

[Marjeris Romero]

The UART signals are routed through the interface MCU,  can you try connecting your micro USB cable to the J2 connector instead?

If you are still having issues, could you please upload a picture or drawing of your setup so we can try to reproduce it?