IMU 측정, 커맨드 및 응답 추가

boards/nrf52840dk_nrf52840.overlay

@@ -5,13 +5,17 @@
  * Pin mapping:
  *   POWER_HOLD:   P0.08 (output, active high - latches power)
  *   POWER_BTN:    P1.08 (input, active low - pressed = LOW)
- *   LED_BLE:    P0.12 (output, active low)
+ *   LED_BLE:      P0.12 (output, active low)
  *   LED_ORANGE:   P0.29 (output, active low)
  *   BATT_ADC:     P0.04 (AIN2, battery voltage measurement)
+ *   IMU_SCL:      P1.14 (I2C0 clock)
+ *   IMU_SDA:      P1.15 (I2C0 data)
  */
 
 #include <zephyr/dt-bindings/adc/adc.h>
 #include <zephyr/dt-bindings/adc/nrf-saadc.h>
+/* nRF 핀 컨트롤 매크로 (NRF_PSEL - I2C/SPI 등 핀 재배치에 필요) */
+#include <zephyr/dt-bindings/pinctrl/nrf-pinctrl.h>
 
 /* P0.08이 DK 기본 UART0 RX로 잡혀있어서 GPIO 출력 충돌 → 비활성화 */
 &uart0
@@ -19,6 +23,27 @@
 	status = "disabled";
 };
 
+/* I2C0 핀 재설정: ICM42670P IMU (SCL=P1.14, SDA=P1.15) */
+&i2c0_default {
+	group1 {
+		psels = <NRF_PSEL(TWIM_SCL, 1, 14)>,
+		        <NRF_PSEL(TWIM_SDA, 1, 15)>;
+	};
+};
+
+&i2c0_sleep {
+	group1 {
+		psels = <NRF_PSEL(TWIM_SCL, 1, 14)>,
+		        <NRF_PSEL(TWIM_SDA, 1, 15)>;
+		low-power-enable;
+	};
+};
+
+&i2c0 {
+	status = "okay";
+	clock-frequency = <I2C_BITRATE_STANDARD>;
+};
+
 /* 배터리 ADC 채널 설정 (AIN2 = P0.04) */
 &adc
 {