TMS320F28377D: _IQ15SinPU calculation results are difficult to understand

Yale Li 李耀先

Expert 4660 points

Part Number: TMS320F28377D
Other Parts Discussed in Thread: C2000WARE

Hi Team,

My customer test in cpu1.

test1=_IQ15SinPU(1), the result observed in CCS Expression window is 6.

test1=_IQ15SinPU(3.1415926), the result observed in CCS Expression window is 18.

How are these results calculated?

Thanks & Regards

over 1 year ago

0 Rajeshwary Nitin Bongirwar over 1 year ago

TI__Expert 5590 points

Hi Yale,

Our SME is currently OOO till 7th November he will revert you once he resumes office.

Regards,

Rajeshwary

+1 Sira Rao80 over 1 year ago in reply to Rajeshwary Nitin Bongirwar

TI__Mastermind 26130 points

Yale,

_IQ15SinPU(3.1415926) -> the input argument here is not correct ,it needs to be an IQ15 number. And it needs to be in Per-unit radians, i.e. normalized by (2 x pi).

Please refer to the IQMath user guide in C2000Ware for an explanation of the IQNsinPU function. Pasting a picture below taken from there.

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TMS320F28377D: _IQ15SinPU calculation results are difficult to understand