How to get uart_example to work on NRF51822?

RE: How to get uart_example to work on NRF51822?

Anne van Rossum — Fri, 10 Oct 2014 11:32:23 GMT

Off topic: What I can recommend is also to buy the (very cheap) Saleae logic analyzer. I was following devzone.nordicsemi.com/.../a00009.html as a good boy, but discovered in the end that I failed to set the baud rate right, e.g. 0x009D5000UL for 38400 baud. Not only can you see if you didn't switch TX and RX by accident. The automatic baud rate detection of the logic analyzer software can solve these problems in no time!

RE: How to get uart_example to work on NRF51822?

Francis — Tue, 27 Aug 2013 13:30:53 GMT

Thank you! That got me on the right track. I had some minor differences.

Without any changes to the UART example that I have, the pin assignments are (taken from nrf6310.h included by the uart_example):

#define RX_PIN_NUMBER 16 // UART RX pin number. #define TX_PIN_NUMBER 17 // UART TX pin number. #define CTS_PIN_NUMBER 18 // UART Clear To Send pin number. #define RTS_PIN_NUMBER 19 // Not used if HWFC is set to false

For a nrf51822-DK (PCA10005) connected to a nrf6310, I connected P15's RXD and TXD to P2.0 and P2.1, respectively. I also connected P15's CTS and RTS to P2.2 and P2.3, respectively.

RE: How to get uart_example to work on NRF51822?

Ole Morten — Tue, 27 Aug 2013 06:49:43 GMT

If you're using the Development Kit, and flashing to that module, you need to connect a serial cable or USB-to-UART bridge to the serial port on the motherboard and also make sure that the appropriate pins of the nRF51822 (pin 15 and 16 by default) are connected to the RXD/TXD on P15. This is shown in section 2.9 in the nRFgo Starter Kit User Guide. Your UART settings seems correct for such setup.

The J-Link CDC port you see is most likely the one that your development dongle exposes, so if you flash the pca10000 UART example to it, you should see UART data coming out of it. This port requires hardware flow control