diff options
Diffstat (limited to 'Demos/Device/LowLevel/AudioInput/AudioInput.c')
| -rw-r--r-- | Demos/Device/LowLevel/AudioInput/AudioInput.c | 56 |
1 files changed, 55 insertions, 1 deletions
diff --git a/Demos/Device/LowLevel/AudioInput/AudioInput.c b/Demos/Device/LowLevel/AudioInput/AudioInput.c index f62fcbec5..d79167660 100644 --- a/Demos/Device/LowLevel/AudioInput/AudioInput.c +++ b/Demos/Device/LowLevel/AudioInput/AudioInput.c @@ -39,6 +39,9 @@ /** Flag to indicate if the streaming audio alternative interface has been selected by the host. */ static bool StreamingAudioInterfaceSelected = false; +/** Current audio sampling frequency of the streaming audio endpoint. */ +static uint32_t CurrentAudioSampleFrequency = 48000; + /** Main program entry point. This routine contains the overall program flow, including initial * setup of all components and the main program loop. @@ -87,7 +90,7 @@ void EVENT_USB_Device_Connect(void) /* Sample reload timer initialization */ TIMSK0 = (1 << OCIE0A); - OCR0A = ((F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1); + OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1); TCCR0A = (1 << WGM01); // CTC mode TCCR0B = (1 << CS01); // Fcpu/8 speed } @@ -152,6 +155,57 @@ void EVENT_USB_Device_ControlRequest(void) Endpoint_ClearSETUP(); Endpoint_ClearStatusStage(); } + + break; + case AUDIO_REQ_SetCurrent: + if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT)) + { + /* Extract out the relevant request information to get the target Endpoint index and control being set */ + uint8_t EndpointIndex = (uint8_t)USB_ControlRequest.wIndex; + uint8_t EndpointControl = (USB_ControlRequest.wValue >> 8); + + /* Only handle SET CURRENT requests to the audio endpoint's sample frequency property */ + if ((EndpointIndex == AUDIO_STREAM_EPNUM) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq)) + { + uint8_t SampleRate[3]; + + Endpoint_ClearSETUP(); + Endpoint_Read_Control_Stream_LE(SampleRate, sizeof(SampleRate)); + Endpoint_ClearOUT(); + + /* Set the new sampling frequency to the value given by the host */ + CurrentAudioSampleFrequency = (((uint32_t)SampleRate[2] << 16) | ((uint32_t)SampleRate[1] << 8) | (uint32_t)SampleRate[0]); + + /* Adjust sample reload timer to the new frequency */ + OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1); + } + } + + break; + case AUDIO_REQ_GetCurrent: + if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT)) + { + /* Extract out the relevant request information to get the target Endpoint index and control being retrieved */ + uint8_t EndpointIndex = (uint8_t)USB_ControlRequest.wIndex; + uint8_t EndpointControl = (USB_ControlRequest.wValue >> 8); + + /* Only handle GET CURRENT requests to the audio endpoint's sample frequency property */ + if ((EndpointIndex == AUDIO_STREAM_EPNUM) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq)) + { + uint8_t SampleRate[3]; + + /* Convert the sampling rate value into the 24-bit format the host expects for the property */ + SampleRate[2] = (CurrentAudioSampleFrequency >> 16); + SampleRate[1] = (CurrentAudioSampleFrequency >> 8); + SampleRate[0] = (CurrentAudioSampleFrequency & 0xFF); + + Endpoint_ClearSETUP(); + Endpoint_Write_Control_Stream_LE(SampleRate, sizeof(SampleRate)); + Endpoint_ClearOUT(); + } + } + + break; } } |