Tool/software: Code Composer Studio
Hello, I'm using '2837x_RFFT_ADC' example code in CCS.
For FFT output, I want to take absolute value for these data.
===================================================================================================================================================
#include "fpu_rfft.h"
#include "math.h"
#include "examples_setup.h"
#define RFFT_STAGES 11
#define RFFT_SIZE (1 << RFFT_STAGES)
#define F_PER_SAMPLE (ADC_SAMPLING_FREQ/(float)RFFT_SIZE)
#pragma DATA_SECTION(RFFTin1Buff,"RFFTdata1")
uint16_t RFFTin1Buff[2*RFFT_SIZE];
#pragma DATA_SECTION(RFFTmagBuff,"RFFTdata2")
float RFFTmagBuff[RFFT_SIZE/2+1];
#pragma DATA_SECTION(RFFToutBuff,"RFFTdata3")
float RFFToutBuff[RFFT_SIZE];
//float RFFToutBuff1[RFFT_SIZE]=fabsf(RFFToutBuff[RFFT_SIZE]);
#pragma DATA_SECTION(RFFTF32Coef,"RFFTdata4")
float RFFTF32Coef[RFFT_SIZE];
RFFT_ADC_F32_STRUCT rfft_adc;
RFFT_ADC_F32_STRUCT_Handle hnd_rfft_adc = &rfft_adc;
RFFT_F32_STRUCT rfft;
RFFT_F32_STRUCT_Handle hnd_rfft = &rfft;
volatile uint16_t flagInputReady = 0;
volatile uint16_t sampleIndex = 0;
uint16_t pass = 0;
uint16_t fail = 0;
__interrupt void adcaIsr();
int16_t main(void)
{
uint16_t i, j;
float freq = 0.0;
#ifdef FLASH
EALLOW;
Flash0EccRegs.ECC_ENABLE.bit.ENABLE = 0;
memcpy((uint32_t *)&RamfuncsRunStart, (uint32_t *)&RamfuncsLoadStart,
(uint32_t)&RamfuncsLoadSize );
FPU_initFlash();
#endif //FLASH
FPU_initSystemClocks();
FPU_initEpie();
FPU_initADCA();
FPU_initEPWM();
EALLOW;
PieVectTable.ADCA1_INT = &adcaIsr;
EDIS;
PieCtrlRegs.PIEIER1.bit.INTx1 = 1;
IER |= M_INT1;
EINT;
ERTM;
FPU_startEPWM();
hnd_rfft_adc->Tail = &(hnd_rfft->OutBuf);
hnd_rfft->FFTSize = RFFT_SIZE; //FFT size
hnd_rfft->FFTStages = RFFT_STAGES; //FFT stages
hnd_rfft_adc->InBuf = &RFFTin1Buff[0]; //Input buffer (12-bit ADC) input
hnd_rfft->OutBuf = &RFFToutBuff[0]; //Output buffer
hnd_rfft->CosSinBuf = &RFFTF32Coef[0]; //Twiddle factor
hnd_rfft->MagBuf = &RFFTmagBuff[0]; //Magnitude output buffer
RFFT_f32_sincostable(hnd_rfft); //Calculate twiddle factor
for (i=0; i < RFFT_SIZE; i++){
RFFToutBuff[i] = 0; //Clean up output buffer
}
for (i=0; i < RFFT_SIZE/2; i++){
RFFTmagBuff[i] = 0; //Clean up magnitude buffer
}
while(1){
while(flagInputReady == 0){};
RFFT_adc_f32(hnd_rfft_adc);
flagInputReady = 0; // Reset the flag
RFFT_f32_mag(hnd_rfft); //Calculate magnitude
j = 1;
freq = RFFTmagBuff[1];
for(i=2;i<RFFT_SIZE/2+1;i++){
if(RFFTmagBuff[i] > freq){
j = i;
freq = RFFTmagBuff[i];
}
}
freq = F_PER_SAMPLE * (float)j;
}
done();
return 1;
}
__interrupt void adcaIsr()
{
RFFTin1Buff[sampleIndex++] = AdcaResultRegs.ADCRESULT0;
if(sampleIndex == (RFFT_SIZE - 1) ){
sampleIndex = 0;
flagInputReady = 1;
}
AdcaRegs.ADCINTFLGCLR.bit.ADCINT1 = 1; //clear INT1 flag
PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
=========================================================================================================================
From this code, FFT output data is stored in 'RFFToutBuff'.
Please help me
Thank you.
