//! The main function
int main(int argc, char *argv[])
{
A_ALIGNED static dsp16_t s_input[N/NB_CUTS];
int f;
dsp_resampling_t *resampling;
dsp16_t *output;
U32 temp;
dsp16_resampling_options_t options;
// Initialize options
memset(&options, 0, sizeof(options));
options.coefficients_generation = DSP16_RESAMPLING_OPTIONS_USE_DYNAMIC;
options.dynamic.coefficients_normalization = true;
// Switch to external Oscillator 0.
pm_switch_to_osc0(&AVR32_PM, FOSC0, OSC0_STARTUP);
// Initialize the DSP debug module
dsp_debug_initialization(FOSC0);
dsp16_debug_printf("16-bit fixed point signal resampling\n");
dsp16_debug_printf("Input Fs: %iHz\n", F_INPUT);
dsp16_debug_printf("Output Fs: %iHz\n", F_OUTPUT);
dsp16_debug_printf("%i samples to process cut into %i buffers\n", N, NB_CUTS);
dsp16_debug_printf("Filter order used: %i\n", FILTER_ORDER);
if (!(resampling = dsp16_resampling_setup(F_INPUT, F_OUTPUT, N/NB_CUTS, FILTER_ORDER, 1, (malloc_fct_t) malloc, &options)))
{
dsp16_debug_printf("Unable to allocate enough memory\n");
return -1;
}
if (!(output = (dsp16_t *) malloc(dsp16_resampling_get_output_max_buffer_size(resampling)*sizeof(dsp16_t) + 4)))
{
dsp16_debug_printf("Unable to allocate enough memory for the output buffer\n");
return -1;
}
for(f=0; f<NB_CUTS; f++)
{
memcpy(s_input, &s[N/NB_CUTS*f], (N/NB_CUTS)*sizeof(dsp16_t));
temp = Get_sys_count();
dsp16_resampling_compute(resampling, output, s_input, 0);
temp = Get_sys_count() - temp;
dsp16_debug_print_vect(output, dsp16_resampling_get_output_current_buffer_size(resampling));
}
dsp16_debug_printf(
"Cycle count per iteration: %i\n in total (to compute %i samples): %i\n",
temp,
dsp16_resampling_get_output_current_buffer_size(resampling)*NB_CUTS,
temp*NB_CUTS);
dsp16_resampling_free(resampling, (free_fct_t) free);
while(1);
}
static bool usb_stream_process(void)
{
buffer_t *input_buffer;
#if (defined __GNUC__)
dsp16_t * volatile dsp16_output_buffer;
#else
dsp16_t * dsp16_output_buffer;
#endif
int i, channel, size = 0;
// If no buffer is ready, then set under flow marker
if (usb_stream_context->current_full_buffer == -1)
return false;
// If the audio DAC is not ready to receive more data, then return
if (!audio_mixer_dacs_output_direct(NULL, 0))
return false;
// Select the current input buffer and make sure it is valid
input_buffer = usb_stream_context->input_buffers[usb_stream_context->current_full_buffer];
// Make sure this buffer is not already in the process of resampling
if (input_buffer->buffer_state != BUFFER_STATE_FULL)
return false;
// Mark this buffer as a "resampling" buffer
input_buffer->buffer_state = BUFFER_STATE_RESAMPLING;
// Select the current output buffer
dsp16_output_buffer = (dsp16_t *) usb_stream_context->output_buffers[usb_stream_context->current_output_buffer];
for (channel=0; channel<usb_stream_context->nb_channels; channel++)
{
// Interpolates the current channel buffer
dsp16_resampling_compute(usb_stream_context->ctx->resampling,
usb_stream_context->output_temp_buffer,
input_buffer->buffer[channel],
channel);
size = dsp16_resampling_get_output_current_buffer_size(usb_stream_context->ctx->resampling);
// Fill the array with audio samples and mix the channels
switch (usb_stream_context->nb_channels)
{
case 1:
memcpy(dsp16_output_buffer, usb_stream_context->output_temp_buffer, usb_stream_context->input_buffer_size);
break;
case 2:
for (i=0; i<size; i++)
dsp16_output_buffer[i*2] = ((dsp16_t *) usb_stream_context->output_temp_buffer)[i];
break;
default:
for (i=0; i<size; i++)
dsp16_output_buffer[i*usb_stream_context->nb_channels] = ((dsp16_t *) usb_stream_context->output_temp_buffer)[i];
}
// change channel
dsp16_output_buffer++;
}
// Re-selects the current output buffer
dsp16_output_buffer = (dsp16_t *) usb_stream_context->output_buffers[usb_stream_context->current_output_buffer];
// Scale the output buffer if the scaling is set
if (usb_stream_context->ctx->gain)
dsp16_vect_realdiv(dsp16_output_buffer, dsp16_output_buffer, size * usb_stream_context->nb_channels, usb_stream_context->ctx->gain);
// Send the buffer to the output channel
audio_mixer_dacs_output_direct(dsp16_output_buffer, size);
// Set the current input buffer as an empty buffer
input_buffer->buffer_state = BUFFER_STATE_EMPTY;
// Update the current output buffer index
usb_stream_context->current_output_buffer = (usb_stream_context->current_output_buffer+1)%AUDIO_STREAM_NB_OUTPUT_BUFFERS;
// Update the current full buffer pointer
i = (usb_stream_context->current_full_buffer+1)%AUDIO_STREAM_NB_INPUT_BUFFERS;
input_buffer = usb_stream_context->input_buffers[i];
if (input_buffer->buffer_state != BUFFER_STATE_FULL)
i = -1;
usb_stream_context->current_full_buffer = i;
return true;
}