Problem with TWI and MPU9150/MPU6050

RE: Problem with TWI and MPU9150/MPU6050

Marius R. — Tue, 03 Jun 2014 12:53:14 GMT

The above link is broken (like every other link in this forum). Can anyone tell me how to get this file anyway.

RE: Problem with TWI and MPU9150/MPU6050

Tom P — Tue, 25 Feb 2014 06:07:59 GMT

Brian,

Thanks for the hint. I think I'm doing it correctly but earlier I wrote some code to try every address just in case :-). Going to try turning off the soft device and disabling the ADC, etc. Hopefully something will work!

Tom

RE: Problem with TWI and MPU9150/MPU6050

Brian — Mon, 24 Feb 2014 11:19:00 GMT

Tom,

I know this may be a silly question, but are you remembering to shift the MPU9150 address from 8bit (0x68) to a 7bit like this:

// Left shift I2C address one bit (7bit result) m_device_address = (uint8_t)(device_address << 1);

RE: Problem with TWI and MPU9150/MPU6050

Tom P — Mon, 24 Feb 2014 11:11:54 GMT

Thanks for the try Brian. Your version seems to behave the same way the stock version does; not able to read or write a 9150 register. At least no more resetting! Perhaps I'm doing something really stupid. No GPIO setup .. just twi initialize and mpu initialize. It's 2am so I'm not thinking clearly. Thanks!

RE: Problem with TWI and MPU9150/MPU6050

Brian — Mon, 24 Feb 2014 10:46:18 GMT

Tom,

If you're willing to give it a shot, here's my sd_twi_hw_master.c file that I modified for my MPU6050/9150 to work correctly. You will notice that I had to comment out the err_code in the twi_master_init(). Also, don't forget to change pin numbers for SDA / SCL on lines 25 and 26 (or comment them out). Fingers crossed...

sd_twi_hw_master.c

RE: Problem with TWI and MPU9150/MPU6050

Tom P — Mon, 24 Feb 2014 10:20:55 GMT

Thanks for the suggestion! Didn't seem to work for me. The twi_master_init() now seems to cause a system reset and gets caught in a loop. I turn on an LED at the start of my program and now it's blinking. Still nothing on the scope and still scratching my head.

RE: Problem with TWI and MPU9150/MPU6050

Brian — Mon, 24 Feb 2014 09:38:28 GMT

Tom,

I ran into similar problems when using the softdevice & TWI. Replacing the twi_hw_master.c file with sd_twi_hw_master.c file should help. Here's the link to the file: sd_twi_hw_master.c

Have fun!