size_t DACClass::queueBuffer(const uint32_t *buffer, size_t size) {
// Try the first PDC buffer
if ((dac->DACC_TCR == 0) && (dac->DACC_TNCR == 0)) {
dac->DACC_TPR = (uint32_t) buffer;
dac->DACC_TCR = size;
dac->DACC_PTCR = DACC_PTCR_TXTEN;
if (cb)
dacc_enable_interrupt(dac, DACC_IER_ENDTX);
return size;
}
// Try the second PDC buffer
if (dac->DACC_TNCR == 0) {
dac->DACC_TNPR = (uint32_t) buffer;
dac->DACC_TNCR = size;
dac->DACC_PTCR = DACC_PTCR_TXTEN;
if (cb)
dacc_enable_interrupt(dac, DACC_IER_ENDTX);
return size;
}
// PDC buffers full, try again later...
return 0;
}
/**
* \brief DACC configuration.
*/
static void dsp_configure_dacc(void)
{
pmc_enable_periph_clk(ID_DACC);
/*
* DACC setting
* -Refresh Period = 1024*REFRESH/DACC Clock
* -No max Speed Mode
* -Startup time of 0 periods of DACClock
*/
dacc_set_timing(DACC, DACC_REFRESH, 0, DACC_MR_STARTUP_0);
/* Set TIO Output of TC Channel 1 as trigger */
dacc_set_trigger(DACC,2);
/* Set to half word transfer */
dacc_set_transfer_mode(DACC, DACC_MR_WORD_HALF);
#if (SAM3S) || (SAM3XA)
/* Set to No Sleep Mode and No Fast Wake Up Mode*/
dacc_set_power_save(DACC, 0, 0);
#endif
/* Select both left/right speaker channels. */
dacc_set_channel_selection(DACC, SPEAKER_CHANNEL_R);
dacc_set_channel_selection(DACC, SPEAKER_CHANNEL_L);
/* Enable DACC channels. */
dacc_enable_channel(DACC, SPEAKER_CHANNEL_R);
dacc_enable_channel(DACC, SPEAKER_CHANNEL_L);
/* Tag selection mode enabled. */
dacc_enable_flexible_selection(DACC);
/* Get board DACC PDC base address. */
dacc_pdc = dacc_get_pdc_base(DACC);
/* Enable DACC interrupt. */
dacc_enable_interrupt(DACC,DACC_IER_ENDTX);
NVIC_SetPriority(DACC_IRQn, INT_PRIORITY_DACC);
NVIC_EnableIRQ(DACC_IRQn);
}
