Here is some messy code I wrote that works with a GLCD. My original post on that topic is here:
dsPIC + GLCD = Spectrum Analyzer :D
Code:
#include <p33FJ64MC802.h>
#include <dsp.h>
#include "fft.h"
#include "sqrtX.h"
_FOSC(OSCIOFNC_ON & FCKSM_CSDCMD & POSCMD_NONE); //Oscillator Configuration
_FOSCSEL(FNOSC_FRC); //Oscillator Selection
_FWDT(FWDTEN_OFF); //Turn off WatchDog Timer
_FGS(GCP_OFF); //Turn off code protect
_FPOR( FPWRT_PWR1 ); //Turn off power up timer
#define CS2 LATBbits.LATB12
#define CS1 LATBbits.LATB11
#define DI LATBbits.LATB10
#define RW LATBbits.LATB9
#define E LATBbits.LATB8
#define LCD_RESETTING PORTBbits.RB4
void e_togg(void)
{
unsigned int x;
E = 1;
for( x=0; x<6; x++){;} //Delay apx 10us
E = 0;
}
void cmd_write(unsigned char data)
{
unsigned int temp;
DI = 0;
RW = 0;
temp = LATB;
temp &= 0xff00;
temp |= data;
LATB = temp;
e_togg();
}
void clearGLCD(void)
{
unsigned int page, y;
for( page=0xB8; page<0xC0; page++)
{
cmd_write(0x40); //Set Y address to 0
cmd_write(page); //Set pages 0-7
//FEDCBA9876543210
LATB = 0b0001110000000000u; //CS1,CS2 & DI=1 All others & data =0
for( y=0; y<64; y++)
{ e_togg(); } //Clear byte
}
}
void WaitTilReady(void)
{
unsigned int x;
TRISB = 0x00ff;
LATB = 0b0000101000000000u; // CS1 = 1; CS2 = 0; RW = 1; DI = 0;
for( x=0; x<72; x++){;} //Delay apx 100us
E = 1;
for( x=0; x<72; x++){;} //Delay apx 100us
while((PORTB & 0x0090) != 0);
RW = 0;
E = 0;
for( x=0; x<72; x++){;} //Delay apx 100us
CS1 = 0;
CS2 = 1;
RW = 1;
DI = 0;
for( x=0; x<72; x++){;} //Delay apx 100us
E = 1;
for( x=0; x<72; x++){;} //Delay apx 100us
while((PORTB & 0x0090) != 0);
// while(LCD_RESETTING);
RW = 0;
E = 0;
TRISB = 0x0000;
}
unsigned char sqrtI( unsigned int sqrtArg )
{
unsigned char answer, x;
unsigned int temp;
if ( sqrtArg < 0x2 ) { return sqrtArg; }
answer = 0x00;
for( x=0x80; x>0; x>>=1 )
{
answer |= x;
temp = answer * answer;
if (temp > sqrtArg)
{ answer ^= x; }
if (temp == sqrtArg)
{ break; }
}
return answer;
}
/* Global Definitions */
unsigned int x,page,RevPage,temp,bin;
unsigned int *TestPtr;
fractcomplex sigCmpx[FFT_BLOCK_LENGTH] __attribute__ ((space(ymemory),far,aligned(FFT_BLOCK_LENGTH * 2 *2)));
#ifndef FFTTWIDCOEFFS_IN_PROGMEM
fractcomplex twiddleFactors[FFT_BLOCK_LENGTH/2] /* Declare Twiddle Factor array in X-space*/
__attribute__ ((section (".xbss, bss, xmemory"), aligned (FFT_BLOCK_LENGTH*2)));
#else
extern const fractcomplex twiddleFactors[FFT_BLOCK_LENGTH/2] /* Twiddle Factor array in Program memory */
__attribute__ ((space(auto_psv), aligned (FFT_BLOCK_LENGTH*2)));
#endif
void initAdc1(void);
int peakFrequencyBin = 0; /* Declare post-FFT variables to compute the */
unsigned long peakFrequency = 0; /* frequency of the largest spectral component */
int main(void)
{
int i = 0;
fractional *p_real = &sigCmpx[0].real ;
fractcomplex *p_cmpx = &sigCmpx[0] ;
AD1PCFGL = 0xfffe; //make ADC pins all digital except RA0
TRISA = 0x0001; //Make all PORTs all outputs except AN0
TRISB = 0;
initAdc1();
WaitTilReady();
LATB = 0b0001110000000000u; //CS1,CS2 & DI=1 All others & data =0
for ( x=0; x<3500; x++){;}
cmd_write(0x3f); //turn on display
clearGLCD();
for ( i=0; i<256; i++)
{ x = sqrtX(i);}
x=0;
for ( i=0; i<256; i++)
{ x = sqrtI(i);}
x=0;
while(1){
// for ( x=0; x<35000; x++){;}
#ifndef FFTTWIDCOEFFS_IN_PROGMEM /* Generate TwiddleFactor Coefficients */
TwidFactorInit (LOG2_BLOCK_LENGTH, &twiddleFactors[0], 0); /* We need to do this only once at start-up */
#endif
for ( i = 0; i < FFT_BLOCK_LENGTH; i++ )/* The FFT function requires input data */
{ /* to be in the fractional fixed-point range [-0.5, +0.5]*/
LATBbits.LATB15 = 1; //ADC Sample flag 1.7uS
AD1CON1bits.DONE = 0;
AD1CON1bits.SAMP = 1; // start sampling then... after 31Tad go to conversion.
while (!AD1CON1bits.DONE); // conversion done?
LATBbits.LATB15 = 0; //ADC Sample flag 200ms
sigCmpx[i].real = (signed)ADC1BUF0 >> 1; /* So, we shift all data samples by 1 bit to the right. */
sigCmpx[i].imag = 0x0000;
}
/* Perform FFT operation */
#ifndef FFTTWIDCOEFFS_IN_PROGMEM
FFTComplexIP (LOG2_BLOCK_LENGTH, &sigCmpx[0], &twiddleFactors[0], COEFFS_IN_DATA);
#else
FFTComplexIP (LOG2_BLOCK_LENGTH, &sigCmpx[0], (fractcomplex *) __builtin_psvoffset(&twiddleFactors[0]), (int) __builtin_psvpage(&twiddleFactors[0]));
#endif
/* Store output samples in bit-reversed order of their addresses */
BitReverseComplex (LOG2_BLOCK_LENGTH, &sigCmpx[0]);
/* Compute the square magnitude of the complex FFT output array so we have a Real output vetor */
SquareMagnitudeCplx(FFT_BLOCK_LENGTH, &sigCmpx[0], &sigCmpx[0].real);
/* Find the frequency Bin ( = index into the SigCmpx[] array) that has the largest energy*/
/* i.e., the largest spectral component */
VectorMax(FFT_BLOCK_LENGTH/2, &sigCmpx[0].real, &peakFrequencyBin);
/* Compute the frequency (in Hz) of the largest spectral component */
peakFrequency = peakFrequencyBin*(SAMPLING_RATE/FFT_BLOCK_LENGTH);
for( x=0; x<465; x++){;} //Delay apx 1ms
E = 0;
CS1 = 1;
CS2 = 1;
for( x=0; x<72; x++){;} //Delay apx 100us
cmd_write(0x40); //Set Y address to 0
cmd_write(0xb8); //go to page 0
for( x=0; x<465; x++){;} //Delay apx 1ms
DI = 1;
RW = 0;
LATBbits.LATB13 = 1; //Display write flag 150ms
TestPtr = (unsigned int *)&sigCmpx[0];
RevPage = 8;
for( page = 0xBF; page >= 0xB8; page-- )
{
CS1 = 1; CS2 = 0; cmd_write(page); cmd_write(0x40);
for( bin = 0; bin <= 127; bin++ )
{
if( bin == 64)
{ CS1 = 0; CS2 = 1; cmd_write(page); cmd_write(0x40); }
DI = 1; RW = 0;
if ( TestPtr[bin] > 0x0FFF ) { x = 0x0FFF; }
else { x = TestPtr[bin] << 3; }
if ( x > 0x0FFF ) { x = 0x0FFF; }
temp = sqrtI(x); //Calculate linear amplitude of frequency bin.
// temp = sqrtI(TestPtr[bin]); //Calculate linear amplitude of frequency bin.
if( temp >= RevPage )
{ LATB |= 0x00FF; } // Make 8 bit bargraph fully ON
else
{
temp = 255 << (RevPage-temp); // Convert to 8 bit bargraph
temp &= 0x00ff;
LATB &= 0xff00;
LATB |= temp;
}
e_togg();
}
RevPage += 8;
}
LATBbits.LATB13 = 0; //Display write flag 150ms
}
return 0;
}
/*=============================================================================
initAdc1() is used to configure A/D to convert channel 5 on Timer event.
It generates event to DMA on every sample/convert sequence. ADC clock is configured at 625Khz
=============================================================================*/
void initAdc1(void)
{
AD1CON1 = 0x00E0; // SSRC bit = 111 implies internal counter ends sampling and starts converting.
AD1CON1bits.FORM = 3; // Data Output Format: Signed Fraction (Q15 format)
AD1CON1bits.AD12B = 1; // 12-bit ADC operation
AD1CON2 = 0; // Converts CH0
AD1CON3bits.SAMC = 4; // Sample time = 4Tad, Tad = internal 2Tcy
AD1CON3bits.ADRC=0; // ADC Clock is derived from Systems Clock
AD1CON3bits.ADCS = 8; // ADC Conversion Clock Tad=Tcy*(ADCS+1)= (1/7.37M)*64 = 8.7us (115Khz)
// ADC Conversion Time for 12-bit Tc=14*Tad = 22.4us
AD1CHS0bits.CH0SA=0; // MUXA +ve input selection (AN0) for CH0
AD1CHS0bits.CH0NA=0; // MUXA -ve input selection (Vref-) for CH0
AD1PCFGL=0xFFFE; // AN0 as Analog Input
IFS0bits.AD1IF = 0; // Clear the A/D interrupt flag bit
IEC0bits.AD1IE = 0; // Do Not Enable A/D interrupt
AD1CON1bits.ADON = 1; // Turn on the A/D converter
}
Like I said the code is messy and contains redundant code such as two versions of square root for testing purposes. The twiddleFactors table comes with the MicroChip DSP library, so I won't include it here.
Code for the assembler version of square root:
Code:
;-----------------------------------------------------------------------;
; sqrtX.s: Integer square root function.
;
; Input:
;
; (w0) unsigned int x
;
; Output:
;
; (w0) unsigned char square root of x
;
; Description:
;
; Computes the square root of the argument x.
;
;-----------------------------------------------------------------------;
.global _sqrtX
_sqrtX:
cp w0,#2
bra geu, _domore
return
_domore:
clr w1 ;answer reg
mov #0x0080,w2 ;loop reg x
_sqrtLoop:
ior w2,w1,w1 ;answer |= x;
mul.uu w1,w1,w4 ;temp w4 = answer * answer;
cp w0,w4 ;if (temp w4 > sqrtArg)
bra geu, _donext
xor w2,w1,w1 ;answer ^= x;
_donext:
cp w0,w4
bra z, _quit ;if (temp w4 == sqrtArg)
lsr w2,w2
bra nz,_sqrtLoop
_quit:
mov w1,w0
return ; Done
;-----------------------------------------------------------------------;
.end
FIR/FFT/IIR on dsPIC
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