IMU Gyro Sensor × Arduino I2C (universal I2C edition)

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The universal I2C edition of the IMU Gyro Sensor speaks MBC I2C protocol v2: write one id, read 2 bytes = one int16 little-endian value; consecutive ids can be read in one go. This page has the value table, commands and wiring for this product; the shared rules (F0~F5 version & status, F8 re-address, EF reboot) are on the universal I2C protocol page.

SPIKEEV3Arduino I2CmBlockMATRIXmicro:bit

Tip

New to coding? Start with the Arduino examples; every sketch is copy-and-upload. The six-host reading of every value is in the reference.

Basics

Wiring

Works directly with 5 V hosts, no level shifter; two products with the same address cannot share a bus (re-address one with F8 first).

Value table

Each id returns one int16; click an id for the six-host reading and figure.

Write commands

Status flags F3

Shared registers

Single-file helper functions

No library to install. Paste it in two parts: part ① (2 lines) at the top of the sketch, part ② at the bottom. #include <Wire.h> and MBC_NONE must appear before setup() uses them; pasting everything at the bottom will not compile.

① At the top of your sketch (before setup())

#include <Wire.h>

const int16_t MBC_NONE = -32768;   // no answer / undefined id

② At the bottom of your sketch (after loop())

// read k consecutive values (k ≤ 16) starting at id, int16 little-endian
bool mbcReadMany(uint8_t addr, uint8_t id, uint8_t k, int16_t *out) {
  Wire.beginTransmission(addr);
  Wire.write(id);
  if (Wire.endTransmission() != 0) return false;
  delay(2);                                        // always wait 2 ms (ESP32 products cannot clock-stretch)
  if (Wire.requestFrom(addr, (uint8_t)(k * 2)) != (uint8_t)(k * 2)) return false;
  for (uint8_t i = 0; i < k; i++) {
    uint8_t lo = Wire.read(), hi = Wire.read();
    out[i] = (int16_t)(lo | (hi << 8));
  }
  return true;
}

// read one value; MBC_NONE when nothing answers
int16_t mbcRead(uint8_t addr, uint8_t id) {
  int16_t v;
  return mbcReadMany(addr, id, 1, &v) ? v : MBC_NONE;
}

// write a command (0~3 parameters)
// with 2 parameters whose first is 0, write (uint8_t)0, e.g. mbcWrite(ADDR, 0xF8, (uint8_t)0x00, 0xFF); otherwise it clashes with the array form below and will not compile
void mbcWrite(uint8_t addr, uint8_t id, const uint8_t *args, uint8_t n) {
  Wire.beginTransmission(addr);
  Wire.write(id);
  for (uint8_t i = 0; i < n; i++) Wire.write(args[i]);
  Wire.endTransmission();
}
void mbcWrite(uint8_t addr, uint8_t id) { mbcWrite(addr, id, nullptr, 0); }
void mbcWrite(uint8_t addr, uint8_t id, uint8_t a) { mbcWrite(addr, id, &a, 1); }
void mbcWrite(uint8_t addr, uint8_t id, uint8_t a, uint8_t b) { uint8_t p[2] = {a, b}; mbcWrite(addr, id, p, 2); }
void mbcWrite(uint8_t addr, uint8_t id, uint8_t a, uint8_t b, uint8_t c) { uint8_t p[3] = {a, b, c}; mbcWrite(addr, id, p, 3); }

// wait until ready (F3 bit0 = 1), at most ms milliseconds
bool mbcWaitReady(uint8_t addr, unsigned long ms) {
  unsigned long t0 = millis();
  while (millis() - t0 < ms) {
    int16_t st = mbcRead(addr, 0xF3);
    if (st != MBC_NONE && (st & 1)) return true;
    delay(20);
  }
  return false;
}

Example: print the whole value table

// helper part ①
#include <Wire.h>

const int16_t MBC_NONE = -32768;   // no answer / undefined id

const uint8_t ADDR = 0x6A;

void setup() {
  Serial.begin(115200);
  Wire.begin();
#if defined(WIRE_HAS_TIMEOUT)
  Wire.setWireTimeout(25000, true);   // AVR: never hang when the module is silent
#endif
  if (!mbcWaitReady(ADDR, 2000)) Serial.println("module not found: check wiring and address");
  Serial.print("ID 0x"); Serial.println(mbcRead(ADDR, 0xF0), HEX);   // low byte address, high byte hw[0]
  Serial.print("FW ");    Serial.println(mbcRead(ADDR, 0xF2));
}

void loop() {
  Serial.print("headingGyro3D: "); Serial.println(mbcRead(ADDR, 0x01));   // gyro 3D heading
  Serial.print("headingFused: "); Serial.println(mbcRead(ADDR, 0x02));   // fused heading
  Serial.print("headingGyro1D: "); Serial.println(mbcRead(ADDR, 0x03));   // gyro 1D heading
  Serial.print("headingMag: "); Serial.println(mbcRead(ADDR, 0x04));   // magnetic heading
  Serial.print("yawRate: "); Serial.println(mbcRead(ADDR, 0x05));   // yaw rate
  Serial.print("pitch: "); Serial.println(mbcRead(ADDR, 0x06));   // pitch angle
  Serial.print("pitchRate: "); Serial.println(mbcRead(ADDR, 0x07));   // pitch rate
  Serial.print("magTrust: "); Serial.println(mbcRead(ADDR, 0x08));   // magnetometer trust
  Serial.print("magDisturb: "); Serial.println(mbcRead(ADDR, 0x09));   // magnetic disturbance
  Serial.print("upFace: "); Serial.println(mbcRead(ADDR, 0x0A));   // face up
  { int16_t a[3]; mbcReadMany(ADDR, 0x10, 3, a); Serial.print("gyro: "); for (uint8_t i = 0; i < 3; i++) { Serial.print(a[i]); Serial.print(' '); } Serial.println(); }
  { int16_t a[3]; mbcReadMany(ADDR, 0x13, 3, a); Serial.print("accel: "); for (uint8_t i = 0; i < 3; i++) { Serial.print(a[i]); Serial.print(' '); } Serial.println(); }
  { int16_t a[3]; mbcReadMany(ADDR, 0x16, 3, a); Serial.print("mag: "); for (uint8_t i = 0; i < 3; i++) { Serial.print(a[i]); Serial.print(' '); } Serial.println(); }
  Serial.print("cmdStatus: "); Serial.println(mbcRead(ADDR, 0x0B));   // command status
  Serial.println();
  delay(200);
}

// paste part ② of the helper functions below

Sources and assumptions

Generated by _build/gen-reference.mjs from _build/protocol/imu.json (single source of truth, transcribed from the 2026-10-21 protocol decisions).

• hw0 = 1（共識 #6）；EV3 模式 4 = [0x6A | 1<<8, 韌體主×100+次, 0, 0]（格式 B 再補 2 個 0），模式 5 改送俯仰角速度（取代 #65 放的 ID）。
• EV3 鎖住模式 0／1／3 照盤點程式碼：0 = 陀螺 3D、1 = 融合航向、3 = [陀螺 1D, 磁力航向]（INO:213 註解寫反，以程式為準）。
• 0x22 照 R4 版（出貨版）鎖住：命令 49 = 三個航向 +32768 的「低 byte 在前、高 byte 在後」；盤點檔分析的是主韌體（高在前），主韌體 #67 改成跟 R4 版逐 byte 相同。命令 1012 = 0；0x01、0x0A、0x0F、F1~F4 都觸發航向歸零（刻意，不動）。
• B-13：E1~E4 加速度計／磁力計校準開始／結束補回（v1 的 0x20 = 01/02/03/04），I2C 定案 §3 只列 E0。busyFlag：E1 → b4、E3 → b5。
• 俯仰角範圍定案沒寫（韌體尚無現成值，#67 用 atan2 新算），range 先填「°」不給 min/max，韌體做好後再補。
• 磁力信任度 08 = round(trust×255)，磁場干擾度 09 = round(disturbance×100) 上限 255，朝上的面 0A = 軸號 + 3×負向：公式照盤點 I2C v1 0x34~0x36。
• 角速度 1012 = round(dps×SIGN×10)、加速度 1315 = mm/s²×1000/9806.65、磁力 1618 = raw×SIGN×4/15：公式照盤點 I2C v1 0x220x24；mBlock 一併有（I2C 定案 §4 共用值表）。
• 主對話 2026-10-22：06 俯仰角範圍 −90~+90、07 = gyro X（照字面），取自 F5 韌體實作。
• Pin table uses each board's common defaults (ESP32: change with Wire.begin(sda, scl)).