I2S mic to USB audio (nRF5 SDK v17.0.2)

[yoyou]

Hello,

nRF5 SDK v17.0.2, Keil5

USB audio demo and I2S demo,

i2s cannect two mic(L and R),  16bit 48K STEREO,

how to put i2s data to usb audio?

i add function to USB audio demo as follow:

uint16_t usb_put_data(const uint16_t* p_buff, uint16_t size)
{
 	ret_code_t ret = app_usbd_audio_class_tx_start(&m_app_audio_microphone.base, p_buff, size*2);
 	if (NRF_SUCCESS == ret)
	{
		//bsp_board_led_invert(LED_AUDIO_RX);
	}
	return size;
}

don't know if it sucess, so some audio data lost.

it note This function should be called in reaction to a SOF event.

where the SOF?

int hp_sof_ev_handler(uint16_t framecnt)

or 

usbd_user_ev_handler(app_usbd_event_type_t event)  ---> case APP_USBD_EVT_DRV_SOF:

   How to do it specifically?

      

Best regards

[Sigurd]

Hi,

I assume you have taken a look at how it's done in the usbd_audio example.

In the usbd_user_ev_handler, you get the event APP_USBD_EVT_DRV_SOF. Here app_usbd_audio_class_rx_start() is called, and when that is completed, you get the APP_USBD_AUDIO_USER_EVT_RX_DONE in hp_audio_user_ev_handler(), and here app_usbd_audio_class_tx_start() is called. In that way, it's called in a reaction to a SOF event, in the usbd_audio example.

[yoyou]

Hi, thanks for reply,

app_usbd_audio_class_rx_start()  and APP_USBD_AUDIO_USER_EVT_RX_DONE 

is recv from PC,then loop back to PC,

i don't need it, my project only recv from I2S and then put the audio data to PC by usb audio.

I2S demo,data_handler()-->check_rx_data(),got audio data,how to put to usb audio?

1.Using app_usbd_audio_class_tx_start() directly,  i suspect losing some data frames.

2.put data to a memery buffer first, then where to call app_usbd_audio_class_tx_start()?

if call it once in first put to buffer,and then call in APP_USBD_AUDIO_USER_EVT_TX_DONE,

will lost most of audio data.

        

Best regards

[Sigurd]

Hi,

Could you check the return code of app_usbd_audio_class_tx_start()?

[yoyou]

Hi, 

a lot of failed that return code 17

   

      

Best regards

[yoyou]

if change to wait for success

will no audio on PC.

[Sigurd]

Are you getting the APP_USBD_AUDIO_USER_EVT_TX_DONE event?

Maybe you can use that event to call app_usbd_audio_class_tx_start() again

[yoyou]

call app_usbd_audio_class_tx_start() got return code 17 when failed,

total count: successed 12402, got APP_USBD_AUDIO_USER_EVT_TX_DONE  12401, failed 10578.

failed means lost data, if call again in DOWN event maybe repeat data or wrong order.

  

is our a old project use nRF52840,  Too many functions to migrate to Zephyr.

please help slove it.