Problem with MPU6050 and nRF51822 to send Data over BLE..

[Muhammad Nabeel]

I am trying to send the MPU6050 data using BLE nRF51822. I have used ble_app_uart example modified it to read the data over I2C and send the data over BLE. I can successfuly read device ID but when i read accelerometer or gyroscope data I am unable to read any register. Please help me 

[awneil]

So your question is actually just about how to read the sensor - not (yet) about how to send data over BLE.

It is important to take these things one step at a time!

Muhammad Nabeel said:

I can successfuly read device ID

So you must have your basic I2C comms working, then.

Muhammad Nabeel said:

but when i read accelerometer or gyroscope data I am unable to read any register

So there must be something wrong with your higher-level code.

You need to check your code carefully against the MPU6050's datasheet - and confirm that you are doing exactly what it says. 

You should also look at the I2C line with an analyser or oscilloscope to see what is acually happening - and, again, confirm that it meets the datasheet requirements.

This is all standard interface debugging stuff - nothing specifically to do with Nordic.

www.avrfreaks.net/.../2418156

[Muhammad Nabeel]

Yeah, you are right. But the same code which reads the accelerometer and gyroscope registers works fine when run separately. Actually I merged two examples together one ble_app_uart and other reads data from MPU6050 and prints the data on the terminal. 

Here are some snippets of the code which reads data.

void MPU6050_ReadAcc( int16_t *pACC_X , int16_t *pACC_Y , int16_t *pACC_Z )
{
    
	uint8_t buf[6];    		
//	uint8_t addr= MPU6050_ADDRESS << 1;

    
	mpu6050_register_read(MPU6050_ACC_OUT, buf, 6);
  *pACC_X = (buf[0] << 8) | buf[1];
	if(*pACC_X & 0x8000) *pACC_X-=65536;
		
	*pACC_Y= (buf[2] << 8) | buf[3];
  if(*pACC_Y & 0x8000) *pACC_Y-=65536;
	
  *pACC_Z = (buf[4] << 8) | buf[5];
	if(*pACC_Z & 0x8000) *pACC_Z-=65536;
}

[Muhammad Nabeel]

BLE is working fine actually i am reading the device ID and send it  over BLE which works. 

Here is the snippet. 

	nrf_delay_ms(50);
	mpu6050_register_read(0x75U, &id, 1); // Read the device ID 
    err_code=ble_nus_string_send(&m_nus, gyrValue.temp2, 6); // Send over BLE
				
    APP_ERROR_CHECK(err_code);				
    nrf_delay_ms(2);			
	id=0;

[awneil]

Muhammad Nabeel said:

the same code which reads the accelerometer and gyroscope registers works fine when run separately.

So you need to find where the BLE is "disrupting" it.

•  Does the combined code read the accelerometer & gyroscope registers fine if you just don't enable the BLE?
• Does the combined code read the accelerometer & gyroscope registers fine if the BLE is enabled, but not actually connected?
• Are you sure that it's not reading the registers - or is it just that your transmission is corrupting the data?

[Muhammad Nabeel]

Let me check and will reply and thanks for the help.