nano33ble: add log uart

uart will be used by loader for logging when SHELL is not enabled

Author: pennam

variants/arduino_nano_33_ble_nrf52840_sense/arduino_nano_33_ble_nrf52840_sense.conf

@@ -19,13 +19,17 @@ CONFIG_USB_DEVICE_VID=0x2341
 CONFIG_USB_DEVICE_PID=0x035A
 
 CONFIG_USB_CDC_ACM=y
-CONFIG_USB_CDC_ACM_RINGBUF_SIZE=512
+CONFIG_USB_CDC_ACM_RINGBUF_SIZE=1024
 CONFIG_UART_LINE_CTRL=y
 CONFIG_CDC_ACM_DTE_RATE_CALLBACK_SUPPORT=y
 
 CONFIG_CPP=n
 CONFIG_SHELL=n
 
+CONFIG_LOG_BACKEND_UART=y
+CONFIG_LOG_BACKEND_UART_AUTOSTART=n
+CONFIG_LOG_DEFAULT_LEVEL=2
+
 CONFIG_ADC=y
 CONFIG_PWM=y
 

variants/arduino_nano_33_ble_nrf52840_sense/arduino_nano_33_ble_nrf52840_sense.overlay

@@ -42,6 +42,17 @@
 	};
 };
 
+/{
+	chosen {
+		zephyr,log-uart = &log_uarts;
+	};
+
+	log_uarts: log_uarts {
+		compatible = "zephyr,log-uart";
+		uarts = <&uart0 &board_cdc_acm_uart>;
+	};
+};
+
 
 / {
 	zephyr,user {