[PIC] FFT input format for dsPIC30F

[helmi_mjd]

Hi! I have one question about reading ADC value as FFT input. I'm using dspIC30F. I found the following definition of the FFT input as given by the Microchip CE018 example.

extern fractcomplex sigCmpx[NUMSAMP] 				 
__attribute__ ((section (".ydata, data, ymemory"),aligned (NUMSAMP * 2 *2)))

I'm not understand this part. I would like to read ADC value into this array, how could I do that?

Thanks in advance

 

[horace1]

it is some years since I used this but I seem to remember copying the ADC data into the .real component and zeroing the .imag component of the input arrays

 

[helmi_mjd]

it is some years since I used this but I seem to remember copying the ADC data into the .real component and zeroing the .imag component of the input arrays

Thanks for your reply. I have the following code, is this what you refer to?

//Acquire signal from ADC pin replace real part  
	//with ADC value, set imiginary part as 0	
        for (i=0;i<NUMSAMP;i++) {
	     sigCmpx[i].real = inputSignal[i];					
	     sigCmpx[i].imag = 0;							
	}

 

[horace1]

Thanks for your reply. I have the following code, is this what you refer to?

//Acquire signal from ADC pin replace real part  
	//with ADC value, set imiginary part as 0	
        for (i=0;i<NUMSAMP;i++) {
	     sigCmpx[i].real = inputSignal[i];					
	     sigCmpx[i].imag = 0;							
	}

yes, I assume this is sample code from one of Microchip's application notes