How to use Q1.15 format data to CORDIC cosine function.

[Leo_Chao]

Excuse me. I have some trouble in CORDIC function.

I Config CORDIC by Q1.31 for input and output data format. CORDIC can't work and the return data is right.

But I change  the CORDIC input data to Q1.15 in config, It can't work. I always get 0.

Below is my config ...

LL_CORDIC_Config(CORDIC, LL_CORDIC_FUNCTION_COSINE, /* cosine function */

LL_CORDIC_PRECISION_4CYCLES, /* max precision for q1.31 cosine */

LL_CORDIC_SCALE_0, /* no scale */

LL_CORDIC_NBWRITE_1, /* One input data: angle. Second input data (modulus) is 1 after cordic reset */

LL_CORDIC_NBREAD_1, /* One output data: cosine, then sine */

LL_CORDIC_INSIZE_16BITS, /* q1.15 format for input data */

LL_CORDIC_OUTSIZE_16BITS); /* q1.15 format for output data */



and this is send data to CORDIC

tempf = input_degree /180.0f;

if(tempf > 1)

{

tempf = tempf-2;

}

else if(tempf <-1)

{

tempf = tempf+2 ;

}

temp_16 = (float)tempf * 32768; //for 16bit

ANGLE_CORDIC = (temp_16); //for 16bit input

/* Write angle */

LL_CORDIC_WriteData(CORDIC, ANGLE_CORDIC);

temp_32= (int32_t)LL_CORDIC_ReadData(CORDIC);

cos_value = (float)((int16_t)(temp_32 & 0xFFFF)) / 32768;

sin_value = (float)(temp_32 >>16) / 32768;

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How to modify it to work for Q1.15 input data format? Thank you.