Invert UART TX Signal

[Marcio Segura]

Good day, I am using a USB to UART IC and it isn't working just because the nRF51822 Tx signal is inverted from this IC. There are some way to invert the UART signals?

[Marcio Segura]

Hi Joe. Attached are the print screens of what happen with emIDE (it didn't configure the "Pin select for TXD) and Keil (working) for the same source code. This configuration is at nRF51_Series_Reference_Manual_V2.1.pdf, page 163 (memory address 0x4000250C).

[Joe Merten]

If you're using the Sdk's uart example, then your uart init function may look like this: simple_uart_config(RTS_PIN_NUMBER, TX_PIN_NUMBER, CTS_PIN_NUMBER, RX_PIN_NUMBER, HWFC); The definition of RTS_PIN_NUMBER et cetera depends on which BOARD_… preprocessor macro has been defined (see boards.h). Typically, this would be performed in the Keil µVision projectfile or some Makefile (if using gcc). As soon as you are using emide (which based on gcc), I don't know if that setup works with makefiles or something else. Nevertheless, you should check if your simple_uart_config() call got the correct pin values. For BOARD_NRF6310 the RS232 related pin config looks like this: #define RX_PIN_NUMBER 16 #define TX_PIN_NUMBER 17 #define CTS_PIN_NUMBER 18 #define RTS_PIN_NUMBER 19 #define HWFC false but for all the other BOARD_PCA100... like this: #define RX_PIN_NUMBER 11 #define TX_PIN_NUMBER 9 #define CTS_PIN_NUMBER 10 #define RTS_PIN_NUMBER 8 #define HWFC true

Joe.

[Joe Merten]

For me, as I'm using gcc with eclipse (on linux host), I have a BOARD := BOARD_NRF6310 in my Makefile and the uart example works with both the sdk's gcc setup and Ole Morten's pure-gcc setup.