UART and RTT

[Kevin Kessler]

I have a NRF51 talking through the UART to another uC, and I'm trying to log messages through Segger RTT. Everything works normally until I start to send some data through the UART, and then RTT stops working, although the UART traffic continues without any problems. If I just comment out the app_uart_put lines, RTT works just fine, so I know it is a conflict between the UART and RTT.

I'm using SDK9 since I'm working with the OpenMesh stuff. I've tried both the UART in normal and FIFO configuration, and I've programatically configured the SEGGER_RTT_ConfigUp/DownBuffers as is done in the nrf_log.c libraries, but nothing has helped.

Here is how the UART is configured:

const app_uart_comm_params_t comm_params =
  {
      RX_PIN_NUMBER,
      TX_PIN_NUMBER,
      0,
      0,
      APP_UART_FLOW_CONTROL_DISABLED,
      false,
      UART_BAUDRATE_BAUDRATE_Baud115200
  };

APP_UART_FIFO_INIT(&comm_params,
                     UART_RX_BUF_SIZE,
                     UART_TX_BUF_SIZE,
                     uart_error_handle,
                     APP_IRQ_PRIORITY_LOW,
                     error_code);

Any suggestions?

[Ole Bauck]

Can you try to update the jlink firmware to the latest version as well as using the newest RTT viewer (located in the install folder of the newest firmware)?

Is your code resetting for some reason? This can be an the application running into an error condition (the default behavior is resetting the chip, see here). I believe in earlier jlink/RTT version the RTT logging stopped working if the chip was reset.