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ADIS16136 GYRO_OUT and GYRO_OUT2 combination using SPI and using the IMU Evaluation Program

Question asked by PeterSate on Feb 3, 2014
Latest reply on Feb 3, 2014 by NevadaMark

Hi. I have configured the ADIS16136 using the IMU Evaluation program in the following way:


SMPL_PRD: 000Fh; 2048 SPS

DECI_RATE: 0006h; decimate to 32 SPS

AVG_CNT:    0005h; -3db at arround 15hz (.007 f/fs)


I have a number a number questions, since I don't know how the datasheet agrees with the IMU Evaluation Program, and I haven't used the gyroscope by SPI yet to confirm how it is normally used:


1) Are the numbers I put after the ; correct? Specially I have my doubts about the filter.


2) If I were using this by SPI, I should read GYRO_OUT, then shift it left by 6 bits, then read GYRO_OUT2, and do a bitwise and. That would give me a 22 bit twos-complement integer, and after converting it to signed multiple by 0.018275 / 2^6 to obtain degrees per second. Is this ok?


3) The IMU Evaluation Program, when configured this way and using data capture with "Use Scaled Data" unticked, seems to be giving me full 32 bits numbers, and that I must use 0.018275 / 2^16 as bit weight to obtain degrees per second. What internal arithmetic is it doing with the contents of GYRO_OUT and GYRO_OUT2? Is that bit weight correct to use with unscaled data from the evaluation program? Is it interpolating the real 22 bit number?




EDIT: I'm attaching a sample .csv of data captured not using the use scaled data checkbox.