/*
LUFA Library
- Copyright (C) Dean Camera, 2010.
+ Copyright (C) Dean Camera, 2011.
dean [at] fourwalledcubicle [dot] com
- www.fourwalledcubicle.com
+ www.lufa-lib.org
*/
/*
- Copyright 2010 Dean Camera (dean [at] fourwalledcubicle [dot] com)
+ Copyright 2011 Dean Camera (dean [at] fourwalledcubicle [dot] com)
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby granted
#include "AudioInput.h"
/** Flag to indicate if the streaming audio alternative interface has been selected by the host. */
-bool StreamingAudioInterfaceSelected = false;
+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.
for (;;)
{
- USB_Audio_Task();
USB_USBTask();
}
}
/* Hardware Initialization */
LEDs_Init();
+ Buttons_Init();
ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32);
ADC_SetupChannel(MIC_IN_ADC_CHANNEL);
USB_Init();
LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
/* Sample reload timer initialization */
- OCR0A = (F_CPU / 8 / AUDIO_SAMPLE_FREQUENCY) - 1;
+ TIMSK0 = (1 << OCIE0A);
+ OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1);
TCCR0A = (1 << WGM01); // CTC mode
TCCR0B = (1 << CS01); // Fcpu/8 speed
}
LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
}
-/** Event handler for the USB_UnhandledControlRequest event. This is used to catch standard and class specific
- * control requests that are not handled internally by the USB library (including the Audio class-specific
- * requests) so that they can be handled appropriately for the application.
+/** Event handler for the USB_ControlRequest event. This is used to catch and process control requests sent to
+ * the device from the USB host before passing along unhandled control requests to the library for processing
+ * internally.
*/
-void EVENT_USB_Device_UnhandledControlRequest(void)
+void EVENT_USB_Device_ControlRequest(void)
{
/* Process General and Audio specific control requests */
switch (USB_ControlRequest.bRequest)
}
break;
+ case AUDIO_REQ_GetStatus:
+ /* Get Status request can be directed at either the interface or endpoint, neither is currently used
+ * according to the latest USB Audio 1.0 standard, but must be ACKed with no data when requested */
+ if ((USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE)) ||
+ (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_ENDPOINT)))
+ {
+ 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 address and control being set */
+ uint8_t EndpointAddress = (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 ((EndpointAddress == (ENDPOINT_DESCRIPTOR_DIR_IN | AUDIO_STREAM_EPNUM)) && (EndpointControl == AUDIO_EPCONTROL_SamplingFreq))
+ {
+ uint8_t SampleRate[3];
+
+ Endpoint_ClearSETUP();
+ Endpoint_Read_Control_Stream_LE(SampleRate, sizeof(SampleRate));
+ Endpoint_ClearIN();
+
+ /* 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_DEVICETOHOST | REQTYPE_CLASS | REQREC_ENDPOINT))
+ {
+ /* Extract out the relevant request information to get the target Endpoint address and control being retrieved */
+ uint8_t EndpointAddress = (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 ((EndpointAddress == (ENDPOINT_DESCRIPTOR_DIR_IN | 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;
}
}
-/** Task to manage the Audio interface, reading in ADC samples from the microphone, and them to the host. */
-void USB_Audio_Task(void)
+/** ISR to handle the reloading of the data endpoint with the next sample. */
+ISR(TIMER0_COMPA_vect, ISR_BLOCK)
{
- /* Device must be connected and configured for the task to run */
- if (USB_DeviceState != DEVICE_STATE_Configured)
- return;
-
- /* Check to see if the streaming interface is selected, if not the host is not receiving audio */
- if (!(StreamingAudioInterfaceSelected))
- return;
+ uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint();
/* Select the audio stream endpoint */
Endpoint_SelectEndpoint(AUDIO_STREAM_EPNUM);
- /* Check if the current endpoint can be written to and that the next sample should be stored */
- if (Endpoint_IsINReady() && (TIFR0 & (1 << OCF0A)))
+ /* Check if the current endpoint can be written to and that the audio interface is enabled */
+ if (Endpoint_IsINReady() && StreamingAudioInterfaceSelected)
{
- /* Clear the sample reload timer */
- TIFR0 |= (1 << OCF0A);
-
- /* Audio sample is ADC value scaled to fit the entire range */
- int16_t AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
-
- #if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
- /* Microphone is biased to half rail voltage, subtract the bias from the sample value */
- AudioSample -= (SAMPLE_MAX_RANGE / 2);
+ int16_t AudioSample;
+
+ #if defined(USE_TEST_TONE)
+ static uint8_t SquareWaveSampleCount;
+ static int16_t CurrentWaveValue;
+
+ /* In test tone mode, generate a square wave at 1/256 of the sample rate */
+ if (SquareWaveSampleCount++ == 0xFF)
+ CurrentWaveValue ^= 0x8000;
+
+ /* Only generate audio if the board button is being pressed */
+ AudioSample = (Buttons_GetStatus() & BUTTONS_BUTTON1) ? CurrentWaveValue : 0;
+ #else
+ /* Audio sample is ADC value scaled to fit the entire range */
+ AudioSample = ((SAMPLE_MAX_RANGE / ADC_MAX_RANGE) * ADC_GetResult());
+
+ #if defined(MICROPHONE_BIASED_TO_HALF_RAIL)
+ /* Microphone is biased to half rail voltage, subtract the bias from the sample value */
+ AudioSample -= (SAMPLE_MAX_RANGE / 2);
+ #endif
#endif
/* Write the sample to the buffer */
- Endpoint_Write_Word_LE(AudioSample);
+ Endpoint_Write_16_LE(AudioSample);
/* Check to see if the bank is now full */
if (!(Endpoint_IsReadWriteAllowed()))
Endpoint_ClearIN();
}
}
+
+ Endpoint_SelectEndpoint(PrevEndpoint);
}
projects / pub / USBasp.git / blobdiff