void audio_send_tone(wave_type_t type, unsigned int hz) {
unsigned* waveform;
if (type == WAVE_TRIANGLE) {
waveform = waveform_triangle;
} else if (type == WAVE_SINE) {
waveform = waveform_sine;
} else if (type == WAVE_SAW) {
waveform = waveform_saw;
} else {
waveform = waveform_square;
}
if (audio_set_clock(hz)) {
// Start the clock
// enable (ENAB) + oscillator
// raspbian has this as plla
*(clk + BCM2835_PWMCLK_CNTL) = PM_PASSWORD |
BCM2835_CM_ENAB |
BCM2835_CM_OSCILLATOR;
delay_us(2000);
// disable PWM
*(pwm + BCM2835_PWM_CONTROL) = 0;
delay_us(2000);
// We are dividing each "step" of the sinusoid into 128
// pulse slots.
*(pwm+BCM2835_PWM0_RANGE) = 0x80;
*(pwm+BCM2835_PWM1_RANGE) = 0x80;
// Re-enable PWM
*(pwm+BCM2835_PWM_CONTROL) =
BCM2835_PWM1_USEFIFO |
BCM2835_PWM1_ENABLE |
BCM2835_PWM0_USEFIFO |
BCM2835_PWM0_ENABLE |
1 << 6; // Clear the FIFO of any old data
delay_us(2000);
int i = 0;
while(1) {
int status = *(pwm + BCM2835_PWM_STATUS);
if (!(status & BCM2835_FULL1)) {
*(pwm+BCM2835_PWM_FIFO) = waveform[i];
i++;
i = i % 64;
}
if ((status & ERRORMASK)) {
*(pwm+BCM2835_PWM_STATUS) = ERRORMASK;
}
}
}
}
static void *
dummy_audio_thread(void *aux)
{
audio_decoder_t *ad = aux;
media_pipe_t *mp = ad->ad_mp;
media_queue_t *mq = &mp->mp_audio;
media_buf_t *mb;
int hold = 0;
int run = 1;
int64_t rt = 0;
int64_t base = AV_NOPTS_VALUE;
hts_mutex_lock(&mp->mp_mutex);
while(run) {
if((mb = TAILQ_FIRST(&mq->mq_q)) == NULL) {
hts_cond_wait(&mq->mq_avail, &mp->mp_mutex);
continue;
}
if(mb->mb_data_type == MB_AUDIO && hold && mb->mb_skip == 0) {
hts_cond_wait(&mq->mq_avail, &mp->mp_mutex);
continue;
}
TAILQ_REMOVE(&mq->mq_q, mb, mb_link);
mq->mq_packets_current--;
mp->mp_buffer_current -= mb->mb_size;
mq_update_stats(mp, mq);
hts_cond_signal(&mp->mp_backpressure);
hts_mutex_unlock(&mp->mp_mutex);
switch(mb->mb_data_type) {
case MB_CTRL_EXIT:
run = 0;
break;
case MB_CTRL_PAUSE:
hold = 1;
break;
case MB_CTRL_PLAY:
hold = 0;
base = AV_NOPTS_VALUE;
break;
case MB_FLUSH:
base = AV_NOPTS_VALUE;
break;
case MB_AUDIO:
if(mb->mb_skip || mb->mb_stream != mq->mq_stream)
break;
if(mb->mb_pts != AV_NOPTS_VALUE) {
audio_set_clock(mp, mb->mb_pts, 0, mb->mb_epoch);
if(base == AV_NOPTS_VALUE) {
base = mb->mb_pts;
rt = showtime_get_ts();
} else {
int64_t d = mb->mb_pts - base;
if(d > 0) {
int sleeptime = rt + d - showtime_get_ts();
if(sleeptime > 0)
usleep(sleeptime);
}
}
}
break;
default:
abort();
}
hts_mutex_lock(&mp->mp_mutex);
media_buf_free_locked(mp, mb);
}
hts_mutex_unlock(&mp->mp_mutex);
return NULL;
}
