Can I use UART with an external module linked up to nRF51DK via SWD?

RE: Can I use UART with an external module linked up to nRF51DK via SWD?

MartinBL — Tue, 05 May 2015 06:41:26 GMT

Which target device I chose doesn't seem to affect my setup. What build code do you have on our chip? Sometimes I have experienced that I need to close and reopen RTT viewer to get it working, but I don't remember when i occurs and I'm not able to reproduce it now.

RE: Can I use UART with an external module linked up to nRF51DK via SWD?

muhkuhns — Mon, 04 May 2015 14:12:34 GMT

Got it working and running in a minute. Well that was easy, thanks! At least on the nRF51-DK. But not yet on the module...

Got it. For the DK I chose the target in the RTT Viewer as in the Guide but for my module I switched to my chip. Looks like I wasn't suppose to do that. Can you confirm this with your beacon? Everything working now!

RE: Can I use UART with an external module linked up to nRF51DK via SWD?

MartinBL — Mon, 04 May 2015 13:28:32 GMT

@muhkuhns: Yes, that is correct. I have it running like that as we speak (I use a nrf Beacon with a rev 2 IC).

RE: Can I use UART with an external module linked up to nRF51DK via SWD?

RK — Mon, 04 May 2015 13:15:13 GMT

Of course UART can't be routed via SWD. There are some logging protocols ARM provides which do run over the debug interface, but the NRF51 doesn't have any of them and I don't often see them used anyway. None of them have anything to do with a UART which is entirely a different thing.

RTT is a Segger thing. Look up Segger RTT, it's documented on their site. It's very easy to use and I see now there's even a tutorial someone has kindly written for Nordic's chips. yes it uses the USB on the PC but not the serial port piece, it uses the Segger J-Link piece directly. All it really does is read a chunk of memory off the chip at regular intervals like any other chunk of memory can be read, the Segger RTT code sets up a ring buffer to dump text into, bidirectionally. It's actually very simple, just that Segger have made it into a defined API and integrated it into their debugger.

RE: Can I use UART with an external module linked up to nRF51DK via SWD?

muhkuhns — Mon, 04 May 2015 12:58:51 GMT

I was hoping I could just use UART, but it seems it can't be "routed" via SWD and the nRF51-DK.

But RTT would work this way: PC <-USB-> nRF51-DK <-SWD-> nRF51822 Module ?

RE: Can I use UART with an external module linked up to nRF51DK via SWD?

MartinBL — Mon, 04 May 2015 12:46:17 GMT

Hi.

Maybe J-Link Real Time Terminal is what you seek? Tutorial here: Debugging with Real Time Terminal.

If this is not applicable to you, what module are you using? Correct values for the pins totally depends on what GPIOs are available on your module. And remember that you can route the UART signals on the nRF51 to any GPIO pins you want and you don't necessarily need the RTS and CTS pins.