i2s_mode_t mode; /*!< I2S Working mode*/
uint32_t sample_rate; /*!< I2S sample rate */
bool use_apll; /*!< I2S use APLL clock */
+ bool tx_desc_auto_clear; /*!< I2S auto clear tx descriptor on underflow */
int fixed_mclk; /*!< I2S fixed MLCK clock */
} i2s_obj_t;
// All buffers are empty. This means we have an underflow on our hands.
if (xQueueIsQueueFullFromISR(p_i2s->tx->queue)) {
xQueueReceiveFromISR(p_i2s->tx->queue, &dummy, &high_priority_task_awoken);
+ // See if tx descriptor needs to be auto cleared:
+ // This will avoid any kind of noise that may get introduced due to transmission
+ // of previous data from tx descriptor on I2S line.
+ if (p_i2s->tx_desc_auto_clear == true) {
+ memset((void *) dummy, 0, p_i2s->tx->buf_size);
+ }
}
xQueueSendFromISR(p_i2s->tx->queue, (void*)(&finish_desc->buf), &high_priority_task_awoken);
if (p_i2s->i2s_queue) {
}
p_i2s_obj[i2s_num]->use_apll = i2s_config->use_apll;
+ p_i2s_obj[i2s_num]->tx_desc_auto_clear = i2s_config->tx_desc_auto_clear;
p_i2s_obj[i2s_num]->fixed_mclk = i2s_config->fixed_mclk;
return ESP_OK;
}
int dma_buf_count; /*!< I2S DMA Buffer Count */
int dma_buf_len; /*!< I2S DMA Buffer Length */
bool use_apll; /*!< I2S using APLL as main I2S clock, enable it to get accurate clock */
+ bool tx_desc_auto_clear; /*!< I2S auto clear tx descriptor if there is underflow condition (helps in avoiding noise in case of data unavailability) */
int fixed_mclk; /*!< I2S using fixed MCLK output. If use_apll = true and fixed_mclk > 0, then the clock output for i2s is fixed and equal to the fixed_mclk value.*/
} i2s_config_t;