Hi, I'm working with the nRF9151DK and Zephyr RTOS (v3.7.99 / NCS 2.9.1). I’ve configured UART1 to send and receive data via GPIO pins:
-
TX: pin 8 (P0.08)
-
RX: pin 9 (P0.09)
devicetree.overlay:
/ {
chosen {
zephyr,console = &uart1;
};
};
&uart1 {
status = "okay";
current-speed = <115200>;
pinctrl-0 = <&uart1_default>;
pinctrl-1 = <&uart1_sleep>;
pinctrl-names = "default", "sleep";
};
&pinctrl {
uart1_default: uart1_default {
group1 {
psels = <NRF_PSEL(UART_TX, 0, 8)>,
<NRF_PSEL(UART_RX, 0, 9)>;
};
};
uart1_sleep: uart1_sleep {
group1 {
psels = <NRF_PSEL(UART_TX, 0, 8)>,
<NRF_PSEL(UART_RX, 0, 9)>;
low-power-enable;
};
};
};
prj.conf:
CONFIG_SERIAL=y
CONFIG_UART_CONSOLE=n
CONFIG_USB_DEVICE_STACK=n
CONFIG_PRINTK=y
main.c:
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/kernel.h>
#define UART_NODE DT_NODELABEL(uart1)
void main(void) {
const struct device *uart_dev = DEVICE_DT_GET(UART_NODE);
if (!device_is_ready(uart_dev)) {
return;
}
uint8_t ch;
int ret;
while (1) {
uart_poll_out(uart_dev, 'H');
uart_poll_out(uart_dev, 'i');
uart_poll_out(uart_dev, '\n');
ret = uart_poll_in(uart_dev, &ch);
if (ret == 0) {
uart_poll_out(uart_dev, ch); // Simple echo
uart_poll_out(uart_dev, '\n');
}
k_sleep(K_MSEC(1000));
}
}
Current Behavior:
-
Data is transmitted correctly through pin 8 (UART1 TX) using an external USB-to-Serial adapter.
-
But data is only received via
/dev/ttyACM1, which seems to correspond to the USB interface (UART0?).
Question:
Why does Zephyr still receive input through /dev/ttyACM1 even though UART0 is disabled and UART1 is enabled and routed to GPIO pins?
Am I missing a configuration step to fully detach the USB UART console and use only physical UART1 (pins 8/9) for both TX and RX?
Thank you in advance for your help! 
