diff options
Diffstat (limited to 'lib/lufa/Demos/Device/LowLevel/AudioInput/AudioInput.c')
| -rw-r--r-- | lib/lufa/Demos/Device/LowLevel/AudioInput/AudioInput.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/lib/lufa/Demos/Device/LowLevel/AudioInput/AudioInput.c b/lib/lufa/Demos/Device/LowLevel/AudioInput/AudioInput.c new file mode 100644 index 0000000000..2cf2414663 --- /dev/null +++ b/lib/lufa/Demos/Device/LowLevel/AudioInput/AudioInput.c @@ -0,0 +1,259 @@ +/* + LUFA Library + Copyright (C) Dean Camera, 2017. + + dean [at] fourwalledcubicle [dot] com + www.lufa-lib.org +*/ + +/* + Copyright 2017 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 + without fee, provided that the above copyright notice appear in + all copies and that both that the copyright notice and this + permission notice and warranty disclaimer appear in supporting + documentation, and that the name of the author not be used in + advertising or publicity pertaining to distribution of the + software without specific, written prior permission. + + The author disclaims all warranties with regard to this + software, including all implied warranties of merchantability + and fitness. In no event shall the author be liable for any + special, indirect or consequential damages or any damages + whatsoever resulting from loss of use, data or profits, whether + in an action of contract, negligence or other tortious action, + arising out of or in connection with the use or performance of + this software. +*/ + +/** \file + * + * Main source file for the Audio Input demo. This file contains the main tasks of the demo and + * is responsible for the initial application hardware configuration. + */ + +#include "AudioInput.h" + +/** 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. + */ +int main(void) +{ + SetupHardware(); + + LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY); + GlobalInterruptEnable(); + + for (;;) + { + USB_USBTask(); + } +} + +/** Configures the board hardware and chip peripherals for the demo's functionality. */ +void SetupHardware(void) +{ +#if (ARCH == ARCH_AVR8) + /* Disable watchdog if enabled by bootloader/fuses */ + MCUSR &= ~(1 << WDRF); + wdt_disable(); + + /* Disable clock division */ + clock_prescale_set(clock_div_1); +#endif + + /* Hardware Initialization */ + LEDs_Init(); + Buttons_Init(); + ADC_Init(ADC_FREE_RUNNING | ADC_PRESCALE_32); + ADC_SetupChannel(MIC_IN_ADC_CHANNEL); + USB_Init(); + + /* Start the ADC conversion in free running mode */ + ADC_StartReading(ADC_REFERENCE_AVCC | ADC_RIGHT_ADJUSTED | ADC_GET_CHANNEL_MASK(MIC_IN_ADC_CHANNEL)); +} + +/** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs, and + * configures the sample update and PWM timers. + */ +void EVENT_USB_Device_Connect(void) +{ + /* Indicate USB enumerating */ + LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING); + + /* Sample reload timer initialization */ + TIMSK0 = (1 << OCIE0A); + OCR0A = ((F_CPU / 8 / CurrentAudioSampleFrequency) - 1); + TCCR0A = (1 << WGM01); // CTC mode + TCCR0B = (1 << CS01); // Fcpu/8 speed +} + +/** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via + * the status LEDs, disables the sample update and PWM output timers and stops the USB and Audio management tasks. + */ +void EVENT_USB_Device_Disconnect(void) +{ + /* Stop the sample reload timer */ + TCCR0B = 0; + + /* Indicate streaming audio interface not selected */ + StreamingAudioInterfaceSelected = false; + + /* Indicate USB not ready */ + LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY); +} + +/** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration + * of the USB device after enumeration - the device endpoints are configured. + */ +void EVENT_USB_Device_ConfigurationChanged(void) +{ + bool ConfigSuccess = true; + + /* Setup Audio Stream Endpoint */ + ConfigSuccess &= Endpoint_ConfigureEndpoint(AUDIO_STREAM_EPADDR, EP_TYPE_ISOCHRONOUS, AUDIO_STREAM_EPSIZE, 2); + + /* Indicate endpoint configuration success or failure */ + LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR); +} + +/** 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_ControlRequest(void) +{ + /* Process General and Audio specific control requests */ + switch (USB_ControlRequest.bRequest) + { + case REQ_SetInterface: + /* Set Interface is not handled by the library, as its function is application-specific */ + if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_STANDARD | REQREC_INTERFACE)) + { + Endpoint_ClearSETUP(); + Endpoint_ClearStatusStage(); + + /* Check if the host is enabling the audio interface (setting AlternateSetting to 1) */ + StreamingAudioInterfaceSelected = ((USB_ControlRequest.wValue) != 0); + } + + 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 == AUDIO_STREAM_EPADDR) && (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 == AUDIO_STREAM_EPADDR) && (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; + } +} + +/** ISR to handle the reloading of the data endpoint with the next sample. */ +ISR(TIMER0_COMPA_vect, ISR_BLOCK) +{ + uint8_t PrevEndpoint = Endpoint_GetCurrentEndpoint(); + + /* Select the audio stream endpoint */ + Endpoint_SelectEndpoint(AUDIO_STREAM_EPADDR); + + /* Check if the current endpoint can be written to and that the audio interface is enabled */ + if (Endpoint_IsINReady() && StreamingAudioInterfaceSelected) + { + 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_16_LE(AudioSample); + + /* Check to see if the bank is now full */ + if (!(Endpoint_IsReadWriteAllowed())) + { + /* Send the full packet to the host */ + Endpoint_ClearIN(); + } + } + + Endpoint_SelectEndpoint(PrevEndpoint); +} + |