RE: UART communication with external device on nRF9160dk

Susheel Nuguru — Fri, 07 Mar 2025 07:43:22 GMT

Thanks for coming back to us with a full report V

RE: UART communication with external device on nRF9160dk

verigoify — Thu, 06 Mar 2025 21:05:07 GMT

Hi Susheel,

Thanks for getting back to me.

Your suggested solution from this thread has solved my issue. Many thanks!

For future reference, adding:

CONFIG_UART_0_NRF_HW_ASYNC=y
CONFIG_UART_0_NRF_HW_ASYNC_TIMER=1

to prj.conf is the exact solution to my problem. With this addition, observability printout is:

events generated on tmo = 100 
total_rcved_len = 73 
uart_rx_rdy_evt = 73 
uart_rx_buf_req_evt = 2 
uart_tx_done_evt = 2
uart_tx_aborted_evt = 0 
uart_rx_stopped_evt = 0 
--uart_rx_stopped_overrun = 0 
--uart_rx_stopped_parity = 0 
--uart_rx_stopped_framing = 0 
--uart_rx_stopped_break_condition = 0 
--uart_rx_stopped_collision = 0 
--uart_rx_stopped_noise = 0 
--uart_rx_stopped_other = 0 
uart_rx_disabled_evt = 1

In the spirit of full disclosure, I've swapped logger backend to uart3 and used uart0 for communication, like this:

/{
    chosen {
        zephyr,console = &uart3;
        zephyr,shell-uart = &uart3;
    };
};
&uart0 {
	current-speed = <2400>;
    parity = "even";
    stop-bits = "1";
    data-bits = <8>;
};

&uart0_sleep {
    group1 {
        psels = <NRF_PSEL(UART_TX, 0, 13)>,
                <NRF_PSEL(UART_RX, 0, 10)>,
                <NRF_PSEL(UART_RTS, 0, 20)>,
                <NRF_PSEL(UART_CTS, 0, 21)>;
    };
};

&uart0_default {
    group1 {
        psels = <NRF_PSEL(UART_TX, 0, 13)>, <NRF_PSEL(UART_RX, 0, 10)>;
    };
};

&uart3 {
	status = "okay";
	current-speed = <115200>;
    parity = "even";
    stop-bits = "1";
    data-bits = <8>;
	pinctrl-0 = <&uart3_default>;
	pinctrl-names = "default";
};

&pinctrl {

	uart3_default: uart3_default {

        group2 {
            psels = <NRF_PSEL(UART_TX, 0, 18)>, <NRF_PSEL(UART_RX, 0, 19)>;
        };
	};
};

I don't know if that had anything to do with solving the issue, but there you have it.

Cheers,

RE: UART communication with external device on nRF9160dk

Susheel Nuguru — Thu, 06 Mar 2025 09:53:38 GMT

I do not see anything wrong with your prj.conf and code. Maybe try enabling the hardware flow control as mentioned in this thread.
My colleague in this thread, suggested to enable hw_async mode which seemed to have helped. I do not see anything else apart from these two to help us at this point. If this have not helped, then maybe I need to get more context and code from your end to understand the issue.