kriswiner
commented
8 years ago If you bought the purple boards from China then yes, they are junk.
Make sure the SDA and SCL lines both show 3V3 with a voltmeter when powered on.
It is likely you don't have the I2C address of the MPU9250 right. It can be either 0x68 or 0x69. If you run an I2C scan, what do you get? Here's how:
` // I2C scan function
void I2Cscan()
{
// scan for i2c devices
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" !");
nDevices++;
}
else if (error==4)
{
Serial.print("Unknow error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");
}`
John-Val
sakshirawal14
AcidPrank
Patrickyp
MitalPattani
Hi Kris, I try to use read data from a 9 dof which has written MPY 92/65 on the breakout board. On the back it has written 9250/9255/6500/6555. So I think I should be able to use your example code. But testing it on two Arduino Uno's and with 3 different breakout boards I keep on getting:
Could not connect to MPU9250: 0xFF.
Both with or without the suggested alterations: We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file. We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ to 400000L /twi.h utility file.
The uno boards have separate SCL SDA pins. I used those but I also used A4 and A5 as in the sketch. I use the 3.3 V power supply.
Am I doing something wrong or did I just buy some useless plastic and ceramics?
I hope you can help me out.