ATOM S3 - Problems writing IMU Registers

hriq105

Hello,

I'm currently developing a solution for acceleration data extraction with the M5Stack ATOM S3 module which already includes a MPU 6886 IMU sensor. In its datasheet I'm told it is capable of reaching 4 kHz of sampling rate for the accelerometer. However, while trying to change the registers in what I thought would be the correct settings for highest performance in terms of sampling speeds, it always outputs acceleration in the range of +-8 g and with sampling speed of 250Hz. This is true for any register values I write. Thus, I suspect the writing of such registers is being wrongly handled.

My questions are:

Is there any library that handles the writing of these registers without fail?
Am I choosing the right register addresses and new values?

I also add here a portion of my code corresponding of the writing of the IMU registers:

// Setup for IMU
void setupIMU() {
    Wire.begin();  

    writeRegister(0x6B, 0x09);  // Wake up MPU6886
    delay(10);

    writeRegister(0x1C, 0x18);  // Set accelerometer to ±16g   
    delay(10);

    writeRegister(0x1D, 0x08);  // Disable Low-Pass Filter (more noise)
    delay(10);

    writeRegister(0x6C, 0x07);  // Disable gyroscope
    delay(10);

    writeRegister(0x1B, 0x03);  // Set gyroscope configuration (if needed)
    delay(10);
}

void writeRegister(uint8_t reg, uint8_t value) {
    Wire.beginTransmission(0x68);  // MPU6886 I2C address
    Wire.write(reg);               // Register address
    Wire.write(value);             // Value to write
    Wire.endTransmission();        // End transmission
}

void setup() {

  Serial.begin(115200); // Initialize serial communication at 115200 baud rate
  while (!Serial); // Wait for serial to initialize

  M5.begin();
  auto cfg = M5.config();

  setupIMU();

}

Thank you

hriq105

@hriq105

I found the answer to my problem of writing on the IMU registers on another post here:

https://community.m5stack.com/topic/6959/finding-imu-3d-example-code

However, I'm still having some problems with finding out how to set them up to get the full 4 kHz of acceleration data mentioned in the datasheet. If anyone knows this, please let me know.