diff options
| author | Zixun LI <[email protected]> | 2025-11-07 07:15:15 -0800 |
|---|---|---|
| committer | GitHub <[email protected]> | 2025-11-07 07:15:15 -0800 |
| commit | 91c3a4fa8d1a88880f262b2a3a227374128de3f3 (patch) | |
| tree | 3d6132b3b5aae1c455b1244d9d713cd3cb809cd5 /examples/device | |
| parent | 1634d1175d581a881dc697194d7b59f632f68456 (diff) | |
| parent | f188a400ec4076a289923f2add2aadac6d38f0ce (diff) | |
Merge pull request #3321 from gabChouin/audio_ep_in_target_fifo_size
audio: Implement support for variable EP in flow control fifo level
Diffstat (limited to 'examples/device')
| -rw-r--r-- | examples/device/uac2_speaker_fb/src/main.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/examples/device/uac2_speaker_fb/src/main.c b/examples/device/uac2_speaker_fb/src/main.c index f2cfb155e..7b4e2d64c 100644 --- a/examples/device/uac2_speaker_fb/src/main.c +++ b/examples/device/uac2_speaker_fb/src/main.c @@ -35,13 +35,6 @@ // MACRO CONSTANT TYPEDEF PROTOTYPES //--------------------------------------------------------------------+ -// List of supported sample rates for UAC2 -const uint32_t sample_rates[] = {44100, 48000, 88200, 96000}; - -#define N_SAMPLE_RATES TU_ARRAY_SIZE(sample_rates) - -uint32_t current_sample_rate = 44100; - /* Blink pattern * - 25 ms : streaming data * - 250 ms : device not mounted @@ -76,6 +69,7 @@ static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED; // Current states uint8_t mute[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1]; // +1 for master channel 0 int16_t volume[CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX + 1];// +1 for master channel 0 +uint32_t current_sample_rate = 44100; // Buffer for speaker data uint16_t i2s_dummy_buffer[CFG_TUD_AUDIO_FUNC_1_EP_OUT_SW_BUF_SZ / 2]; @@ -316,6 +310,10 @@ static bool audio10_get_req_entity(uint8_t rhport, tusb_control_request_t const //--------------------------------------------------------------------+ #if TUD_OPT_HIGH_SPEED +// List of supported sample rates for UAC2 +const uint32_t sample_rates[] = {44100, 48000, 88200, 96000}; + +#define N_SAMPLE_RATES TU_ARRAY_SIZE(sample_rates) static bool audio20_clock_get_request(uint8_t rhport, audio20_control_request_t const *request) { TU_ASSERT(request->bEntityID == UAC2_ENTITY_CLOCK); @@ -548,6 +546,17 @@ void tud_audio_feedback_params_cb(uint8_t func_id, uint8_t alt_itf, audio_feedba // Set feedback method to fifo counting feedback_param->method = AUDIO_FEEDBACK_METHOD_FIFO_COUNT; feedback_param->sample_freq = current_sample_rate; + + // About FIFO threshold: + // + // By default the threshold is set to half FIFO size, which works well in most cases, + // you can reduce the threshold to have less latency. + // + // For example, here we could set the threshold to 2 ms of audio data, as audio_task() read audio data every 1 ms, + // having 2 ms threshold allows some margin and a quick response: + // + // feedback_param->fifo_count.fifo_threshold = + // current_sample_rate * CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_RX * CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX / 1000 * 2; } #if CFG_AUDIO_DEBUG |