10DOF IMU #2

I2C it is then. After 3 days of trying to get SPI to work with the drotek imu I gave up and switched to i2c.

As expected it worked from the first try. Well, 10th try actually. It seems that if you disable the FIFO and then try to read it repeatedly weird things happen… This is why it seemed like i2c couldn’t keep up with my data rate.

 

So now I have the accelerometer&gyro sampled at 1000Hz, the compass at 100Hz and the baro/thermometer at 50Hz – all using a 400Khz i2c frequency. It all fits into 200Khz as well so I still have room to increase the sample rate if I need to.

I did a quick test with 800Khz and 1.6Mhz i2c frequencies and to my surprise it worked perfectly. I’ll give this another try when I resume the dead reckoning tests. It should allow me 8Khz gyro/accel sampling frequency.

So right now I’m back to where I was one week ago. Time to resume flight tests in the simulator.

Hopefully next weekend I’ll fly.

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9 thoughts on “10DOF IMU #2

      1. Well, no. I’ve not managed to get the MS5611 to work over SPI either. Im getting 255 when reading. Will try I2C next. Will be interesting to see what Drotek responds.

        1. Did you unsolder the i2c address jumpers as well? After I did this I started to get something other than 0xFF.

          1. I wrote the code for the mpu from scratch using the register map and product spec pdfs and my old mpu6050 code.
            I really have to opensource my code so I can post links to it but unfortunately I don’t have the time to do that now. In a few weeks I hope

  1. No, still nothing. I only got the MS5611 to work but the mpu refused to say anything. I even cut one trace pulling cs_mpu up through one of the 10k resistors and still got nothing. After 3 days of frustration I gave up and switched to i2c.

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