void dac_reload_callback(void)
{
int i;
if (current_stereo_out_buf == stereo_out_buf1)
current_stereo_out_buf = stereo_out_buf2;
else
current_stereo_out_buf = stereo_out_buf1;
generate_signal(signal1_buf, &signal1_generator);
generate_signal(signal2_buf, &signal2_generator);
/* In order for the FIR filter to work correctly we need to keep
* the last part of the previous buffer */
for (i = 0; i < FIR_NUM_COEF; i++) {
signal_pre_filter_buf[i] =
signal_pre_filter_buf[BUFFER_LENGTH + i];
}
/* New data is put in the signal_in_buf which points behind the data
* kept from the previous buffer */
dsp16_vect_add_and_sat(signal_in_buf, signal1_buf, signal2_buf,
BUFFER_LENGTH);
/* Run the FIR filter; the input buffer will be ... longer then the
* output buffer, which has normal length */
if (active_filter > 0) {
dsp16_filt_fir(signal_out_buf, signal_pre_filter_buf,
BUFFER_LENGTH + FIR_NUM_COEF - 1,
filter_coef[active_filter - 1], FIR_NUM_COEF);
} else {
for (i = 0; i < BUFFER_LENGTH; i++)
signal_out_buf[i] = signal_in_buf[i];
}
for (i = 0; i < BUFFER_LENGTH; i++) {
current_stereo_out_buf[i*2] = signal_out_buf[i];
current_stereo_out_buf[i*2+1] = signal_out_buf[i];
}
signals_are_updated = 1;
/* Update PDCA buffer */
tpa6130_dac_output(current_stereo_out_buf, BUFFER_LENGTH);
}
/*! main function */
int main(void)
{
init_sys_clocks();
// Initialize RS232 debug text output.
init_dbg_rs232(FOSC0);
print_dbg(MSG_WELCOME);
// Enable LED0 and LED1
gpio_enable_gpio_pin(LED0_GPIO);
gpio_enable_gpio_pin(LED1_GPIO);
// Configure TWI as master
twi_init();
// Initialize TPA6130
tpa6130_init();
// Initialize DAC that send audio to TPA6130
tpa6130_dac_start(DEFAULT_DAC_SAMPLE_RATE_HZ,
DEFAULT_DAC_NUM_CHANNELS,
DEFAULT_DAC_BITS_PER_SAMPLE,
DEFAULT_DAC_SWAP_CHANNELS,
master_callback,
AUDIO_DAC_OUT_OF_SAMPLE_CB
| AUDIO_DAC_RELOAD_CB,
FOSC0);
tpa6130_set_volume(0x2F);
tpa6130_get_volume();
int count = 0;
int i=0;
while(true)
{
count = 0;
// Store sample from the sound_table array
while(count < (SOUND_SAMPLES)){
samples[count++] = ((uint8_t)sound_table[i]+0x80) << 8;
samples[count++] = ((uint8_t)sound_table[i]+0x80) << 8;
i++;
if (i >= sizeof(sound_table)) i = 0;
}
gpio_set_gpio_pin(LED0_GPIO);
gpio_clr_gpio_pin(LED1_GPIO);
// Play buffer
tpa6130_dac_output((void *) samples,SOUND_SAMPLES/2);
gpio_clr_gpio_pin(LED0_GPIO);
gpio_set_gpio_pin(LED1_GPIO);
/* Wait until the reload register is empty.
* This means that one transmission is still ongoing
* but we are already able to set up the next transmission
*/
while(!tpa6130_dac_output(NULL, 0));
}
}