ITG3200 , measuring real angle problem

hello measuring real angle using itg3200 , , have problem

when rotate +90deg / sec, prints +100deg instead of +90. (not talking drift, gyro incrementing more 10 degrees normal when rotate +90)

i using current sensibility values datasheet, code like:
itg3200 configuration +/-2000deg/sec,98hz

quote

gyro_rate = (gyro_read - gyro_zero) / 14.375                   // 14.375 lsb = 1deg/sec
angle = angle + gyro_rate * looptime;

any help?

thank you,
chaud

i presume variables float?

you have tune constant match actual sensor - sensor's absolute accuracy may not high think, , ratiometric supply voltage sensor best used aref eliminate source of systematic error.
try increasing 14.375 10%.

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