int main(void)
{
int nsamp, i;
float *input, *output1, *output2;
initialize(FS_48K, MONO_IN, STEREO_OUT); // Set up the DAC/ADC interface
// Allocate Required Memory
nsamp = getblocksize();
input = (float *)malloc(sizeof(float)*nsamp);
output1 = (float *)malloc(sizeof(float)*nsamp);
output2 = (float *)malloc(sizeof(float)*nsamp);
if (input==NULL || output1==NULL || output2==NULL) {
flagerror(MEMORY_ALLOCATION_ERROR);
while(1);
}
// Filter coefficients
// float b[5][3] = {{1, 2, 1},{1, -2, 1},{1, 0.851559, 1},{1, -1.90211, 1},{1, 1.17557, 1}};
// float a[5][3] = {{1, 2, 1},{1, -2, 1},{1, 0.851559, 1},{1, -1.90211, 1},{1, 1.17557, 1}};
// float g = 0.0264722;
// Biquad structure initialization
BIQUAD_T *f1;
f1 = init_biquad(num_stages, g, a_coef, b_coef, nsamp);
// Infinite Loop to process the data stream, "nsamp" samples at a time
while(1){
/*
* Ask for a block of ADC samples to be put into the working buffer
* getblock() will wait until the input buffer is filled... On return
* we work on the new data buffer.
*/
getblock(input); // Wait here until the input buffer is filled... Then process
// signal processing code to calculate the required output buffers
// copy input to output2 for reference
for(i=0;i<nsamp;i++) {
output2[i] = input[i];
}
DIGITAL_IO_SET(); // Use a scope on PC4 to measure execution time
// Call the biquad filter routine
calc_biquad(f1,input,output1);
DIGITAL_IO_RESET(); // (falling edge.... done processing data )
// pass the processed working buffer back for DAC output
putblockstereo(output1, output2);
}
}
void config_biquad_filter( // Configure BiQuad filter
BIQUAD_PARAM_S * cur_param_ps // Pointer to structure containing current biquad filter parameters
)
{
// Check if BiQuad filter initialised
if (0 == biquad_gs.init_done)
{ // Initialse BiQuad filter
init_biquad( &biquad_gs ); // Initialise biquad data structure
biquad_gs.init_done = 1; // Signal Bi-Quad filter initialised
} // if (0 == biquad_gs->init_done)
// printstr("FM= "); printintln( (int)cur_param_ps->filt_mode ); // MB~
/* When coefficients are re-calculated mid-stream timing may be broken, but works so far!
* Audio clicks can be heard, but I assume normally this would only occur at a program change,
* so this would mask the click.
*/
// recalculate filter coefficiants based on new sample frequency
init_common_coefs( &(biquad_gs.common_coefs_s) ,cur_param_ps );
biquad_gs.params_set = 1; // Signal BiQuad filter parameters configured
} // config_biquad_filter
