uac2_headset example with 2 input channels

[Lurcy38]

Hello,
Before I am completely formed to the art to build usb descriptors, I would like to modify the uac2_headset example . The modification consists to create a input with 2 channels rather than 1. I saw in the example tusb_config.h a define
#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX 1
So, I modified by value hopping that the input will be changed from 1 to 2 channels
But it is not. The usb device is non longer recognized
Any tips to fix this issue ?
Thanks & Regards

[Lurcy38]

it seams i fixed my issue using this modification
#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX 2
and in the TUD_AUDIO_DESC_INPUT_TERM _nchannelslogical = CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX

TUD_AUDIO_DESC_INPUT_TERM(/*_termid*/ UAC2_ENTITY_MIC_INPUT_TERMINAL, /*_termtype*/ AUDIO_TERM_TYPE_IN_GENERIC_MIC, /*_assocTerm*/ 0x00, /*_clkid*/ UAC2_ENTITY_CLOCK, /*_nchannelslogical 0x01*/ **CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX**, /*_channelcfg*/ AUDIO_CHANNEL_CONFIG_NON_PREDEFINED, /*_idxchannelnames*/ 0x00, /*_ctrl*/ 0 * (AUDIO_CTRL_R << AUDIO_IN_TERM_CTRL_CONNECTOR_POS), /*_stridx*/ 0x00),\

[HiFiPhile]

There are other modifications needed in the descriptor, at least feature unit & nchannelsphysical.
You can compare mic 1ch & 4ch descriptors:

tinyusb/src/device/usbd.h

Line 442 in f84eafc

#define TUD_AUDIO_MIC_ONE_CH_DESCRIPTOR(_itfnum, _stridx, _nBytesPerSample, _nBitsUsedPerSample, _epin, _epsize) \

tinyusb/src/device/usbd.h

Line 491 in f84eafc

#define TUD_AUDIO_MIC_FOUR_CH_DESCRIPTOR(_itfnum, _stridx, _nBytesPerSample, _nBitsUsedPerSample, _epin, _epsize) \

[Lurcy38]

many thanks, may application seems to work fine now. I still have a last issue. i need to detect if the speaker or the microphone is streaming ( or connected)
i didn't see any api to check this state.
any tips ?

[HiFiPhile]

You can check if alt settings is not 0 in tud_audio_set_itf_cb():

tinyusb/examples/device/uac2_headset/src/main.c

Line 344 in a6b29ae

bool tud_audio_set_itf_cb(uint8_t rhport, tusb_control_request_t const * p_request)