kriswiner
commented
6 years ago void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, uint8_t
- dest) { Wire.beginTransmission(address); // Initialize the Tx buffer Wire.write(subAddress); // Put slave register address in Tx buffer Wire.endTransmission(false); // Send the Tx buffer, but send a restart to keep connection alive uint8_t i = 0; Wire.requestFrom(address, count); // Read bytes from slave register address while (Wire.available()) { dest[i++] = Wire.read(); } // Put read results in the Rx buffer }
On Wed, Mar 28, 2018 at 11:49 AM, LuckierBread notifications@github.com wrote:
Hi Kris,
I am using the MPU9250 in a custom PCB. with an Arduino Nano as the controller.
VCC --> 3.3 V GND --> GND SCL --> A5 SDA --> A4 ADO --> GND
I am unable to read any part of the accelerometer or gyro, all reads come back as 0. The Who_Am_I register also returns 0.
I am using a logic level converter to change the 5V Arduino lines to 3.3V for the MPU9250, and have made sure that the data sent from the Arduino is making it to the SDA and SCLK pins with an oscilloscope. When data is requested the line gets held low for as long as it would take to send the requested data. I have 5K pull up resistors on each of the two lines.
I have confirmed that all my connections are solid. used an i2c scanner to confirm that a device exists at 0x68. and successfully retrieved data from the magnetometer.
To eliminate possible code errors I have tried several recommended codes including MPU9250BasicAHRS.ino I am currently using test code recommended by kriswiner in a simmaler issue. code shown here.
`#include
include
define MPU9250_ADDRESS 0x68
define MAG_ADDRESS 0x0C
define GYRO_FULL_SCALE_250_DPS 0x00
define GYRO_FULL_SCALE_500_DPS 0x08
define GYRO_FULL_SCALE_1000_DPS 0x10
define GYRO_FULL_SCALE_2000_DPS 0x18
define ACC_FULL_SCALE_2_G 0x00
define ACC_FULL_SCALE_4_G 0x08
define ACC_FULL_SCALE_8_G 0x10
define ACC_FULL_SCALE_16_G 0x18
// This function read Nbytes bytes from I2C device at address Address. // Put read bytes starting at register Register in the Data array. void I2Cread(uint8_t Address, uint8_t Register, uint8_t Nbytes, uint8_t* Data) { // Set register address Wire.beginTransmission(Address); Wire.write(Register); Wire.endTransmission();
// Read Nbytes Wire.requestFrom(Address, Nbytes); uint8_t index=0; while (Wire.available()) Data[index++]=Wire.read(); }
// Write a byte (Data) in device (Address) at register (Register) void I2CwriteByte(uint8_t Address, uint8_t Register, uint8_t Data) { // Set register address Wire.beginTransmission(Address); Wire.write(Register); Wire.write(Data); Wire.endTransmission(); }
// Initial time long int ti; volatile bool intFlag=false;
// Initializations void setup() { // Arduino initializations Wire.begin(); Serial.begin(115200); // Set accelerometers low pass filter at 5Hz I2CwriteByte(MPU9250_ADDRESS,29,0x06); // Set gyroscope low pass filter at 5Hz I2CwriteByte(MPU9250_ADDRESS,26,0x06);
// Configure gyroscope range I2CwriteByte(MPU9250_ADDRESS,27,GYRO_FULL_SCALE_1000_DPS); // Configure accelerometers range I2CwriteByte(MPU9250_ADDRESS,28,ACC_FULL_SCALE_4_G); // Set by pass mode for the magnetometers I2CwriteByte(MPU9250_ADDRESS,0x37,0x02);
// Request continuous magnetometer measurements in 16 bits I2CwriteByte(MAG_ADDRESS,0x0A,0x16);
pinMode(13, OUTPUT); Timer1.initialize(10000); // initialize timer1, and set a 1/2 second period Timer1.attachInterrupt(callback); // attaches callback() as a timer overflow interrupt
// Store initial time ti=millis(); }
// Counter long int cpt=0;
void callback() { intFlag=true; digitalWrite(13, digitalRead(13) ^ 1); }
// Main loop, read and display data void loop() { while (!intFlag); intFlag=false;
// Display Time
Serial.print (millis()-ti,DEC); Serial.print ("\t");
// ___ // ::: Counter :::
// Display data counter // Serial.print (cpt++,DEC); // Serial.print ("\t");
// ____ // ::: accelerometer and gyroscope :::
// Read accelerometer and gyroscope uint8_t Buf[14]; I2Cread(MPU9250_ADDRESS,0x3B,14,Buf);
// Create 16 bits values from 8 bits data
// Accelerometer int16_t ax=-(Buf[0]<<8 | Buf[1]); int16_t ay=-(Buf[2]<<8 | Buf[3]); int16_t az=Buf[4]<<8 | Buf[5];
// Gyroscope int16_t gx=-(Buf[8]<<8 | Buf[9]); int16_t gy=-(Buf[10]<<8 | Buf[11]); int16_t gz=Buf[12]<<8 | Buf[13];
// Display values
// Accelerometer Serial.print (ax,DEC); Serial.print ("\t"); Serial.print (ay,DEC); Serial.print ("\t"); Serial.print (az,DEC); Serial.print ("\t");
// Gyroscope Serial.print (gx,DEC); Serial.print ("\t"); Serial.print (gy,DEC); Serial.print ("\t"); Serial.print (gz,DEC); Serial.print ("\t");
// _____ // ::: Magnetometer :::
// Read register Status 1 and wait for the DRDY: Data Ready
uint8_t ST1; do { I2Cread(MAG_ADDRESS,0x02,1,&ST1); } while (!(ST1&0x01));
// Read magnetometer data uint8_t Mag[7]; I2Cread(MAG_ADDRESS,0x03,7,Mag);
// Create 16 bits values from 8 bits data
// Magnetometer int16_t mx=-(Mag[3]<<8 | Mag[2]); int16_t my=-(Mag[1]<<8 | Mag[0]); int16_t mz=-(Mag[5]<<8 | Mag[4]);
// Magnetometer Serial.print (mx+200,DEC); Serial.print ("\t"); Serial.print (my-70,DEC); Serial.print ("\t"); Serial.print (mz-700,DEC); Serial.print ("\t");
// End of line Serial.println(""); // delay(100); }`
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LuckierBread
Note that there is a BQ32002 Real-time clock also on the i2c line on the 3.3V side of the logic converter. however, it's address should be 0xC0 so that shouldn't really affect it.
The Bi-Directional Logic Converter circuit is here:
I am having a difficult time figuring out if this is a hardware issue or a software issue.
Please let me know if you see a glaring issue that I am missing here.
Hi Kris,
I am using the MPU9250 in a custom PCB. with an Arduino Nano as the controller.
VCC --> 3.3 V GND --> GND SCL --> A5 SDA --> A4 ADO --> GND
I am unable to read any part of the accelerometer or gyro, all reads come back as 0. The Who_Am_I register also returns 0.
I am using a logic level converter to change the 5V Arduino lines to 3.3V for the MPU9250, and have made sure that the data sent from the Arduino is making it to the SDA and SCLK pins with an oscilloscope. When data is requested the line gets held low for as long as it would take to send the requested data. I have 5K pull up resistors on each of the two lines.
I have confirmed that all my connections are solid. used an i2c scanner to confirm that a device exists at 0x68. and successfully retrieved data from the magnetometer.
To eliminate possible code errors I have tried several recommended codes including MPU9250BasicAHRS.ino I am currently using test code recommended by kriswiner in a simmaler issue. code shown here.
`#include
include
define MPU9250_ADDRESS 0x68
define MAG_ADDRESS 0x0C
define GYRO_FULL_SCALE_250_DPS 0x00
define GYRO_FULL_SCALE_500_DPS 0x08
define GYRO_FULL_SCALE_1000_DPS 0x10
define GYRO_FULL_SCALE_2000_DPS 0x18
define ACC_FULL_SCALE_2_G 0x00
define ACC_FULL_SCALE_4_G 0x08
define ACC_FULL_SCALE_8_G 0x10
define ACC_FULL_SCALE_16_G 0x18
// This function read Nbytes bytes from I2C device at address Address. // Put read bytes starting at register Register in the Data array. void I2Cread(uint8_t Address, uint8_t Register, uint8_t Nbytes, uint8_t* Data) { // Set register address Wire.beginTransmission(Address); Wire.write(Register); Wire.endTransmission();
// Read Nbytes Wire.requestFrom(Address, Nbytes); uint8_t index=0; while (Wire.available()) Data[index++]=Wire.read(); }
// Write a byte (Data) in device (Address) at register (Register) void I2CwriteByte(uint8_t Address, uint8_t Register, uint8_t Data) { // Set register address Wire.beginTransmission(Address); Wire.write(Register); Wire.write(Data); Wire.endTransmission(); }
// Initial time long int ti; volatile bool intFlag=false;
// Initializations void setup() { // Arduino initializations Wire.begin(); Serial.begin(115200); // Set accelerometers low pass filter at 5Hz I2CwriteByte(MPU9250_ADDRESS,29,0x06); // Set gyroscope low pass filter at 5Hz I2CwriteByte(MPU9250_ADDRESS,26,0x06);
// Configure gyroscope range I2CwriteByte(MPU9250_ADDRESS,27,GYRO_FULL_SCALE_1000_DPS); // Configure accelerometers range I2CwriteByte(MPU9250_ADDRESS,28,ACC_FULL_SCALE_4_G); // Set by pass mode for the magnetometers I2CwriteByte(MPU9250_ADDRESS,0x37,0x02);
// Request continuous magnetometer measurements in 16 bits I2CwriteByte(MAG_ADDRESS,0x0A,0x16);
pinMode(13, OUTPUT); Timer1.initialize(10000); // initialize timer1, and set a 1/2 second period Timer1.attachInterrupt(callback); // attaches callback() as a timer overflow interrupt
// Store initial time ti=millis(); }
// Counter long int cpt=0;
void callback() { intFlag=true; digitalWrite(13, digitalRead(13) ^ 1); }
// Main loop, read and display data void loop() { while (!intFlag); intFlag=false;
// Display Time
Serial.print (millis()-ti,DEC); Serial.print ("\t");
// ___ // ::: Counter :::
// Display data counter // Serial.print (cpt++,DEC); // Serial.print ("\t");
// ____ // ::: accelerometer and gyroscope :::
// Read accelerometer and gyroscope uint8_t Buf[14]; I2Cread(MPU9250_ADDRESS,0x3B,14,Buf);
// Create 16 bits values from 8 bits data
// Accelerometer int16_t ax=-(Buf[0]<<8 | Buf[1]); int16_t ay=-(Buf[2]<<8 | Buf[3]); int16_t az=Buf[4]<<8 | Buf[5];
// Gyroscope int16_t gx=-(Buf[8]<<8 | Buf[9]); int16_t gy=-(Buf[10]<<8 | Buf[11]); int16_t gz=Buf[12]<<8 | Buf[13];
// Accelerometer Serial.print (ax,DEC); Serial.print ("\t"); Serial.print (ay,DEC); Serial.print ("\t"); Serial.print (az,DEC);
Serial.print ("\t");
// Gyroscope Serial.print (gx,DEC); Serial.print ("\t"); Serial.print (gy,DEC); Serial.print ("\t"); Serial.print (gz,DEC);
Serial.print ("\t");
// _____ // ::: Magnetometer :::
// Read register Status 1 and wait for the DRDY: Data Ready
uint8_t ST1; do { I2Cread(MAG_ADDRESS,0x02,1,&ST1); } while (!(ST1&0x01));
// Read magnetometer data
uint8_t Mag[7];
I2Cread(MAG_ADDRESS,0x03,7,Mag);
// Create 16 bits values from 8 bits data
// Magnetometer int16_t mx=-(Mag[3]<<8 | Mag[2]); int16_t my=-(Mag[1]<<8 | Mag[0]); int16_t mz=-(Mag[5]<<8 | Mag[4]);
// Magnetometer Serial.print (mx+200,DEC); Serial.print ("\t"); Serial.print (my-70,DEC); Serial.print ("\t"); Serial.print (mz-700,DEC);
Serial.print ("\t");
// End of line Serial.println(""); // delay(100);
}`