nRF51822 - UART Init error

RE: nRF51822 - UART Init error

bjorn-spockeli — Wed, 10 Aug 2016 11:20:18 GMT

@confusedindividual and @stunt_man : Are you able to provide a logic trace/capture of the UART lines when the issue occurs?

RE: nRF51822 - UART Init error

Definitely Confused — Wed, 27 Jul 2016 18:18:48 GMT

I am seeing this error as well. Adding the pull-up line does not fix the problem for me. Outside of using a lower baud rate and likely different pin numbers, my set up is the same as @stunt_man.

RE: nRF51822 - UART Init error

bjorn-spockeli — Mon, 11 Jul 2016 10:35:30 GMT

@stunt_man: It should not be necessary to configure any of the UART pins as inputs/outputs prior to calling uart_init(), as this is done internally in the uart_init() function.

RE: nRF51822 - UART Init error

stunt_man — Wed, 20 Apr 2016 11:53:22 GMT

Not yet. Before calling uart_init(), I added this line of code: nrf_gpio_cfg_input(UART_RX_PIN, NRF_GPIO_PIN_PULLUP);

It seems that uart_init() does not crash the device anymore. Unfortunately, when I add this line, I can not enter debug mode anymore, device is not seen by JLink anymore.

So, I am not able to confirm it solves the problem right now. uart_init() does not crash the device anymore as I successfully turned on a LED just after this step but I can not see if UART is operational.

RE: nRF51822 - UART Init error

bjorn-spockeli — Tue, 19 Apr 2016 07:54:10 GMT

@stunt_man: Have you been able to solve the problem?

RE: nRF51822 - UART Init error

Paolo D — Thu, 14 Apr 2016 18:46:40 GMT

The error code indicates that the FRAMING and BREAK bits in the UART error register are set. This suggests that maybe the UART RX pin is being held low. For normal UART operation it should always be held high by the transmitting device when it's idle, except for when the transmitting device pulls it low for short pulses to send data. So if your GPS module hasn't started driving the pin yet and it's floating then this error might occur. Try enabling the internal pull-up on the UART RX pin to see if that fixes the error.