RE: nRF52840 UART connection

Liu Tengfei — Fri, 15 Dec 2017 06:33:29 GMT

Thank you, Sigurd. I have figured out where I was wrong. The right way of UART connection should be "RX-TX, TX-RX, CTS-RTS, RTS-CTS", just to remind others who might get into the same trouble like me. link to my question this link of my another question will be useful for the UART related problems.

RE: nRF52840 UART connection

Sigurd — Fri, 08 Dec 2017 10:04:46 GMT

Hi,

On the nRF52840-PDK you have 2 USB connectors. The first one is connected to the on-board Segger J-Link debugger/programmer. In the documentation, this MCU is referred to as the “Interface MCU”. See this page at infocenter. The interface MCU features a USB to UART Bridge (virtual COM port). While you can choose any free GPIO pins you want for a regular UART connection on the PDK, the UART connection between the interface MCU and the nRF52840 is fixed, and given in Table 1 here:

The other USB interface(nRF USB) is connected directly to the USB pins on the nRF52840. The signal/USB pins consist of the D+ and D- pins. They are dedicated pins, and not available as standard GPIOs. The USBD peripheral can act as a virtual COM port using the nRF USB connector. This is shown in the USB CDC ACM example in the SDK. In this case, we are not using any UART instance.

2 ) Does the "FTDI usb to uart convertor" use flow-control and Parity excluded ? Do you have a logic analyzer(e.g. Saleae) so you can use to see what is happening on the wires ?

3 ) Then you need to create a new serial uart instance. This is done by using the macro NRF_SERIAL_UART_DEF().

NRF_SERIAL_UART_DEF(serial_uart0, 0); // Create instance of a serial uart  using UARTE0
NRF_SERIAL_UART_DEF(serial_uart1, 1); // Create instance of a serial uart  using UARTE1

ret = nrf_serial_init(&serial_uart0, &m_uart0_drv_config, &serial_config0);
APP_ERROR_CHECK(ret);

ret = nrf_serial_init(&serial_uart1, &m_uart1_drv_config, &serial_config1);
APP_ERROR_CHECK(ret);

RE: nRF52840 UART connection

mweger — Tue, 05 Dec 2017 19:50:55 GMT

I'm having the same issue it seems changing the uart pins from the default ones causes a hard fault for some reason. Really annoying if you ask me.