nRF51 dongle compatibility to convert USB data to DB9 with UART support

[GowthamPV]

We are having nRF51 dongle which is having USB compatible. But My test systems only have the option for DB9 with UART support. Is there any possible to convert nRF51 Dongle USB output to DB9 UART  ? 

[awneil]

GowthamPV said:

DB9

You mean RS232 on a 9-pin D-type connector?

Note that it's DE9 - not DB9 (B is the 25-way size): 

https://en.wikipedia.org/wiki/D-subminiature#DE-9

You would need an RS232 transceiver to convert the nRF51's 3V logic levels to/from RS232

[GowthamPV]

Thanks, Yes it DE9, to connect rs232 transiever. What is the TX and Rx line of Nrf51 dongle in the Nordic standard firmware ??

[Vidar Berg]

RX and TX are connected to the on-board j-link by default, and are used by most of our SDK examples to output debug messages to the PC over UART->USB. But you will need to select some other accessible pins  (p0.15-20) if you are going to have your UART output connected to a rs232 bridge.

Default pinout from the pca10031.h board header:

// UART connection with J-Link
#define RX_PIN_NUMBER  11
#define TX_PIN_NUMBER  9
#define CTS_PIN_NUMBER 10
#define RTS_PIN_NUMBER 8
#define HWFC           true

[GowthamPV]

Could you please share the detailed interface diagram to connect with PC UART connector with NRF dongle. ( What happen if use default Tx and rx pin ?).

OR  What if we use standard UART to USB connector to connect with NRF dongle. Please share your input on this.

i am in need to connect Nrf dongle to my test system's UART port

[Vidar Berg]

Sorry, but I'm not sure I understand what you trying do. As said earlier, you can't use the default TX and RX pins if you are planning to connect the UART interface to an external rs232 converter (link). In that case, you will have to select some new GPIOs that are not already in use.

Schematics and board layout is available on the product page here: https://www.nordicsemi.com/Software-and-tools/Development-Kits/nRF51-Dongle