How to enable both physical uart0 and ble nus service uart

[Teijokk]

Hi, I'm using nrf52810 ,nrf connect, zephyr, vscode extension. I’m having trouble using both UART0 and the NUS UART service.  Here’s a snippet from my overlay file:

/ {

    chosen {

        nordic,nus-uart = &uart0;

    };

};

&uart0 {

    compatible = "nordic,nrf-uarte";

    current-speed = <115200>;

    status = "okay";

    pinctrl-0 = <&uart0_default>;

    pinctrl-1 = <&uart0_sleep>;

    pinctrl-names = "default", "sleep";

};

I previously tested this code on an NRF52840, which has two physical UARTs (UART0 and UART1), where NUS used UART0 and the physical UART was set to UART1.

How can I bind the NUS UART service to something other than UART0? When both are on the same UART peripheral, the code doesn’t work.

Is it possible to create a "dummy UART1" in the DTS file since the NUS service doesn’t use a hardware UART peripheral?

br

Teijo

[Zachary Parrish]

Hi Teijo,

Since the nRF52810 has only one UART, you can't use both UART0 and NUS on the same peripheral. Try this in your DTS:

dts

/ {
chosen {
nordic,nus-uart = &uart1;
};
};

&uart0 {
status = "okay";
};

&uart1 {
status = "disabled"; // Dummy UART for NUS
};
This lets NUS use a "dummy" UART without conflicting with UART0.

Hope that helps!

monkey mart

[Teijokk]

Thank you for the answer.

I added this definition (without an @base address) to the nrf52810.dtsi file, and it still compiles fine:

uart1: uart_dummy {

            status = "disabled";

};

Overlay file:

/ {

    chosen {

        nordic,nus-uart = &uart1;

    };

};

prj file: 

CONFIG_UART_ASYNC_API=y

CONFIG_NRFX_UARTE0=n

#CONFIG_NRFX_UARTE1=n

CONFIG_SERIAL=y

In the uart_peripheral example, CONFIG_NRFX_UARTE0 was set to y. I tried setting CONFIG_NRFX_UARTE1=y.

Can you provide advice on these configurations?

I get a compilation error related to this line:

static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_nus_uart));

C:/ncs/v2.5.0/zephyr/include/zephyr/device.h:85:41: error: '__device_dts_ord_65' undeclared here (not in a function); did you mean '__device_dts_ord_15'?
85 | #define DEVICE_NAME_GET(dev_id) _CONCAT(__device_, dev_id)
| ^~~~~~~~~
C:/ncs/v2.5.0/zephyr/include/zephyr/toolchain/common.h:132:26: note: in definition of macro '_DO_CONCAT'
132 | #define _DO_CONCAT(x, y) x ## y
| ^
C:/ncs/v2.5.0/zephyr/include/zephyr/device.h:85:33: note: in expansion of macro '_CONCAT'
85 | #define DEVICE_NAME_GET(dev_id) _CONCAT(__device_, dev_id)
| ^~~~~~~
C:/ncs/v2.5.0/zephyr/include/zephyr/device.h:211:37: note: in expansion of macro 'DEVICE_NAME_GET'
211 | #define DEVICE_DT_NAME_GET(node_id) DEVICE_NAME_GET(Z_DEVICE_DT_DEV_ID(node_id))
| ^~~~~~~~~~~~~~~
C:/ncs/v2.5.0/zephyr/include/zephyr/device.h:228:34: note: in expansion of macro 'DEVICE_DT_NAME_GET'
228 | #define DEVICE_DT_GET(node_id) (&DEVICE_DT_NAME_GET(node_id))
| ^~~~~~~~~~~~~~~~~~
C:/sw/ble/peripheral_uart_issue/src/main.c:63:36: note: in expansion of macro 'DEVICE_DT_GET'
63 | static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_nus_uart));
| ^~~~~~~~~~~~~~~~~~

Any help is appreciate.

br

Teijo

[Priyanka]

Hi Teijo,

The problem is that nRF52810 has only one hardware UART and it's not possible to use the UART peripheral together for multiple stuff. 

You suggestion of using a dummy UART (say, uart1) for the NUS in the dts file could help (though I have not tried it here). You could maybe set it's status as disabled in the dts so that it does not attempt to assign a physical pin to it. I see that you have tried this and you get errors. Could you share your overlay file?

Another idea would be to maybe try time-sharing the UART0 and NUS.

Regards,

Priyanka