Hi,
I'm using the "C28x Floating Point Unit Library" from sprc624.zip on my F28335. I would like to know What is the InBuffer 's format in 28335 fft library .
For example ,256 fft,I collected 256 data in same interval by ADC.Then I Stored these data in InBuffer and Call RFFT_f32 function and RFFT_f32_mag function to Calculate.But the result is wrong.Here is a right example,but i don't know how to do so that my data is appropriate.
for(i=0;i<FFT_SIZE;i++)
{
InBuffer[i] = a1 * sin(2 * PI * f1 * i / FFT_SIZE) + a2 * sin(2 * PI * f2 * i / FFT_SIZE)+a3 * sin(2 * PI * f3 * i / FFT_SIZE);
}
fft.InBuf = InBuffer; /* Input data buffer */
fft.OutBuf = OutBuffer; /* FFT output buffer */
fft.CosSinBuf = TwiddleBuffer;/* Twiddle factor buffer */
fft.FFTSize = FFT_SIZE; /* FFT length */
fft.FFTStages = FFT_STAGES; /* FFT Stages */
fft.MagBuf = MagBuffer; /* Magnitude buffer */
RFFT_f32_sincostable(&fft); /* Initialize twiddle buffer */
................
interrupt void cpu_timer0_isr(void)
{
unsigned int i;
CpuTimer0.InterruptCount++;
for(i = 0; i < FFT_SIZE; i++)
{
InBuffer[i] = a1 * sin( 2 * PI * f1 * i / FFT_SIZE) + a2 * sin( 2 * PI * f2 * i / FFT_SIZE)+a3*sin(2*PI*f3*i/FFT_SIZE);
}
RFFT_f32(&fft); /* Calculate output */
RFFT_f32s_mag(&fft); /* Calculate magnitude */
// Acknowledge this interrupt to receive more interrupts from group 1
PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
The above example is correct.How can I do?
Thank you for the help! Any idea is well accepted.....
