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.