Added new callback to the Audio Class driver to allow for endpoint control manipulations such as data sample rates.

Modified the Class Driver AudioInput and AudioOutput demos to support multiple sample rates.

Fixed KeyboardHost and KeyboardHostWithParser demos displaying incorrect values when numerical keys were pressed.

Fix broken LowLevel audio demo descriptors.

Minor documentation fixes.

1 files changed, 73 insertions, 1 deletions

diff --git a/Demos/Device/ClassDriver/AudioOutput/AudioOutput.c b/Demos/Device/ClassDriver/AudioOutput/AudioOutput.c
index dbfd10b8b..43267b2a7 100644
--- a/Demos/Device/ClassDriver/AudioOutput/AudioOutput.c
+++ b/Demos/Device/ClassDriver/AudioOutput/AudioOutput.c
@@ -51,6 +51,9 @@ USB_ClassInfo_Audio_Device_t Speaker_Audio_Interface =
 			},
 	};
 
+/** Current audio sampling frequency of the streaming audio endpoint. */
+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.
@@ -135,7 +138,7 @@ 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
 
@@ -199,3 +202,72 @@ void EVENT_USB_Device_ControlRequest(void)
 	Audio_Device_ProcessControlRequest(&Speaker_Audio_Interface);
 }
 
+/** Audio class driver callback for the setting and retrieval of streaming endpoint properties. This callback must be implemented
+ *  in the user application to handle property manipulations on streaming audio endpoints.
+ *
+ *  When the DataLength parameter is NULL, this callback should only indicate whether the specified operation is valid for
+ *  the given endpoint index, and should return as fast as possible. When non-NULL, this value may be altered for GET operations
+ *  to indicate the size of the retreived data.
+ *
+ *  \note The length of the retrieved data stored into the Data buffer on GET operations should not exceed the initial value
+ *        of the \c DataLength parameter.
+ *
+ *  \param[in,out] AudioInterfaceInfo  Pointer to a structure containing an Audio Class configuration and state.
+ *  \param[in]     EndpointProperty    Property of the endpoint to get or set, a value from Audio_ClassRequests_t.
+ *  \param[in]     EndpointIndex       Index of the streaming endpoint whose property is being referenced.
+ *  \param[in]     EndpointControl     Parameter of the endpoint to get or set, a value from Audio_EndpointControls_t.
+ *  \param[in,out] DataLength          For SET operations, the length of the parameter data to set. For GET operations, the maximum
+ *                                     length of the retrieved data. When NULL, the function should return whether the given property
+ *                                     and parameter is valid for the requested endpoint without reading or modifying the Data buffer.
+ *  \param[in,out] Data                Pointer to a location where the parameter data is stored for SET operations, or where
+ *                                     the retrieved data is to be stored for GET operations.
+ *
+ *  \return Boolean true if the property get/set was successful, false otherwise
+ */
+bool CALLBACK_Audio_GetSetEndpointProperty(USB_ClassInfo_Audio_Device_t* const AudioInterfaceInfo,
+                                           const uint8_t EndpointProperty,
+                                           const uint8_t EndpointIndex,
+                                           const uint8_t EndpointControl,
+                                           uint16_t* const DataLength,
+                                           uint8_t* Data)
+{
+	/* Check the requested endpoint to see if a supported endpoint is being manipulated */
+	if (EndpointIndex == Speaker_Audio_Interface.Config.DataOUTEndpointNumber)
+	{
+		/* Check the requested control to see if a supported control is being manipulated */
+		if (EndpointControl == AUDIO_EPCONTROL_SamplingFreq)
+		{
+			/* Check the requested property to see if a supported property is being manipulated */
+			if (EndpointProperty == AUDIO_REQ_SetCurrent)
+			{
+				/* Check if we are just testing for a valid property, or actually adjusting it */
+				if (DataLength != NULL)
+				{
+					/* Set the new sampling frequency to the value given by the host */
+					CurrentAudioSampleFrequency = (((uint32_t)Data[2] << 16) | ((uint32_t)Data[1] << 8) | (uint32_t)Data[0]);
+
+					/* Adjust sample reload timer to the new frequency */
+					OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);				
+				}
+				
+				return true;
+			}
+			else if (EndpointProperty == AUDIO_REQ_GetCurrent)
+			{
+				/* Check if we are just testing for a valid property, or actually reading it */
+				if (DataLength != NULL)
+				{
+					*DataLength = 3;
+
+					Data[2] = (CurrentAudioSampleFrequency >> 16);
+					Data[1] = (CurrentAudioSampleFrequency >> 8);
+					Data[0] = (CurrentAudioSampleFrequency &  0xFF);					
+				}
+				
+				return true;
+			}
+		}
+	}
+	
+	return false;
+}