Hello,
Its me again. I am designing a simple FIR filter implementation using the C6748 DSP and the BIOS platform. The idea is to load filter coefficients based on selections of the DIP switches which is done in a PRD at 1Hz, the audio samples are read in an interrupt which also contains the FIR code. The strange problem I face is that when ever I try to read in data using probe points (be it a single number), I loose output from the audio port. However, if I don't use the probe point and keep the same code, the audio is looped back (for testing purposes). I wanted to know what is the overhead incurred due to using probe points for inputting data. I have attached the code to show the place I have inserted the probe points. Thank you very much.
//---------------------------------------------------------
// main.c
//---------------------------------------------------------
#include "alllabcfg.h" //BIOS include file
#include "framework.h"
#define N 147
void dataIO(void);
//Variables
uint8_t sel=255;
uint32_t dip_stat;
//Arrays for holding the filter coefficients and the input samples from both channels
float h[N]; //4*147=588 bytes
float x[2][N]; //1176 bytes
//Pointers for the circular buffer
int8_t pt_cur=0,pt_conv=0;
//---------------------------------------------------------
//---------------------------------------------------------
void main(void)
{
uint8_t i;
for(i=0;i<N;i++)
{
x[0][i]=0;
x[1][i]=0;
h[i]=0;
}
initAll();
return; // return to BIOS scheduler
}
//---------------------------------------------------------
//---------------------------------------------------------
void dipPRD(void)
{
uint8_t dip_status8;
uint32_t dip_stat_prev;
DIP_getAll(&dip_stat);
DIP_get(DIP_8, &dip_status8);
if(dip_status8)
{
LED_turnOn(LED_2);
sel=1;
}
else
{
LED_turnOff(LED_2);
//sel=0;
}
dip_stat_prev=dip_stat;
//printf("The DIP switch status is read to be %c",dip_status8);
dip_stat=(255-dip_stat)&0x0000000F;
if(dip_stat!=dip_stat_prev)
{
if(dip_stat==1|dip_stat==2|dip_stat==3)
sel=255;
else if(dip_stat==9)
sel=2;
else if(dip_stat==13)
sel=3;
else if(dip_stat==10)
sel=5;
else if(dip_stat==14)
sel=6;
else if(dip_stat==11)
sel=8;
else if(dip_stat==15)
sel=9;
else
sel=255;
dataIO();//Put probe point for data input here
sel=10;//a dummy value to make sure the multiplcation loop is executed
}
}
//---------------------------------------------------------
//---------------------------------------------------------
void audioHWI(void)
{
uint8_t i;
uint32_t s,out;
uint16_t sl,sr,outr,outl;
float output_left=0,output_right=0;
s = read_audio_sample();
if(sel!=1)
{
sl=(uint16_t)(s>>16);
sr=(uint16_t)s;
x[0][pt_cur]=(float)sl;
x[1][pt_cur]=(float)sr;
pt_conv=pt_conv;
for(i=0;i<31;i++)
{
output_left=output_left*output_left;//Test multiplications to check how many can be performed
// in a single interrupt
//output_left+=h[i]*x[0][pt_conv];
//output_right+=h[i]*x[1][pt_conv];
pt_conv--;
if(pt_conv==-1)pt_conv=(N-1);
}
pt_cur++;
outr=(uint32_t)output_right;
outl=(uint32_t)output_left;
out=(uint32_t)(outl&0xFFFF0000)|(outr>>16);
}
write_audio_sample(s); //Loop back the audio to test the program
//}
}
void dataIO()
{
return;
}
