/* LUFA Library Copyright (C) Dean Camera, 2009. dean [at] fourwalledcubicle [dot] com www.fourwalledcubicle.com */ /* Copyright 2009 Dean Camera (dean [at] fourwalledcubicle [dot] com) Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, 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 disclaim 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. */ #include "AudioOutput.h" USB_ClassInfo_Audio_t Speaker_Audio_Interface = { .InterfaceNumber = 0, .DataOUTEndpointNumber = AUDIO_STREAM_EPNUM, .DataOUTEndpointSize = AUDIO_STREAM_EPSIZE, }; int main(void) { SetupHardware(); LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY); for (;;) { if (Speaker_Audio_Interface.InterfaceEnabled) ProcessNextSample(); USB_USBTask(); } } void SetupHardware(void) { /* Disable watchdog if enabled by bootloader/fuses */ MCUSR &= ~(1 << WDRF); wdt_disable(); /* Disable clock division */ clock_prescale_set(clock_div_1); /* Hardware Initialization */ LEDs_Init(); USB_Init(); } void ProcessNextSample(void) { if ((TIFR0 & (1 << OCF0A)) && USB_Audio_IsSampleReceived(&Speaker_Audio_Interface)) { /* Clear the sample reload timer */ TIFR0 |= (1 << OCF0A); /* Retrieve the signed 16-bit left and right audio samples */ int16_t LeftSample_16Bit = (int16_t)USB_Audio_ReadSample16(); int16_t RightSample_16Bit = (int16_t)USB_Audio_ReadSample16(); /* Massage signed 16-bit left and right audio samples into signed 8-bit */ int8_t LeftSample_8Bit = (LeftSample_16Bit >> 8); int8_t RightSample_8Bit = (RightSample_16Bit >> 8); #if defined(AUDIO_OUT_MONO) /* Mix the two channels together to produce a mono, 8-bit sample */ int8_t MixedSample_8Bit = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1); /* Load the sample into the PWM timer channel */ OCRxA = ((uint8_t)MixedSample_8Bit ^ (1 << 7)); #elif defined(AUDIO_OUT_STEREO) /* Load the dual 8-bit samples into the PWM timer channels */ OCRxA = ((uint8_t)LeftSample_8Bit ^ (1 << 7)); OCRxB = ((uint8_t)RightSample_8Bit ^ (1 << 7)); #elif defined(AUDIO_OUT_PORTC) /* Mix the two channels together to produce a mono, 8-bit sample */ int8_t MixedSample_8Bit = (((int16_t)LeftSample_8Bit + (int16_t)RightSample_8Bit) >> 1); PORTC = MixedSample_8Bit; #else uint8_t LEDMask = LEDS_NO_LEDS; /* Make left channel positive (absolute) */ if (LeftSample_8Bit < 0) LeftSample_8Bit = -LeftSample_8Bit; /* Make right channel positive (absolute) */ if (RightSample_8Bit < 0) RightSample_8Bit = -RightSample_8Bit; /* Set first LED based on sample value */ if (LeftSample_8Bit < ((128 / 8) * 1)) LEDMask |= LEDS_LED2; else if (LeftSample_8Bit < ((128 / 8) * 3)) LEDMask |= (LEDS_LED1 | LEDS_LED2); else LEDMask |= LEDS_LED1; /* Set second LED based on sample value */ if (RightSample_8Bit < ((128 / 8) * 1)) LEDMask |= LEDS_LED4; else if (RightSample_8Bit < ((128 / 8) * 3)) LEDMask |= (LEDS_LED3 | LEDS_LED4); else LEDMask |= LEDS_LED3; LEDs_SetAllLEDs(LEDMask); #endif } } void EVENT_USB_Connect(void) { LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING); /* Sample reload timer initialization */ OCR0A = (F_CPU / AUDIO_SAMPLE_FREQUENCY) - 1; TCCR0A = (1 << WGM01); // CTC mode TCCR0B = (1 << CS00); // Fcpu speed #if defined(AUDIO_OUT_MONO) /* Set speaker as output */ DDRC |= (1 << 6); #elif defined(AUDIO_OUT_STEREO) /* Set speakers as outputs */ DDRC |= ((1 << 6) | (1 << 5)); #elif defined(AUDIO_OUT_PORTC) /* Set PORTC as outputs */ DDRC |= 0xFF; #endif #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO)) /* PWM speaker timer initialization */ TCCRxA = ((1 << WGMx0) | (1 << COMxA1) | (1 << COMxA0) | (1 << COMxB1) | (1 << COMxB0)); // Set on match, clear on TOP TCCRxB = ((1 << WGMx2) | (1 << CSx0)); // Fast 8-Bit PWM, Fcpu speed #endif } /** 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_Disconnect(void) { LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY); /* Stop the timers */ TCCR0B = 0; #if (defined(AUDIO_OUT_MONO) || defined(AUDIO_OUT_STEREO)) TCCRxB = 0; #endif #if defined(AUDIO_OUT_MONO) /* Set speaker as input to reduce current draw */ DDRC &= ~(1 << 6); #elif defined(AUDIO_OUT_STEREO) /* Set speakers as inputs to reduce current draw */ DDRC &= ~((1 << 6) | (1 << 5)); #elif defined(AUDIO_OUT_PORTC) /* Set PORTC low */ PORTC = 0x00; #endif } void EVENT_USB_ConfigurationChanged(void) { LEDs_SetAllLEDs(LEDMASK_USB_READY); if (!(USB_Audio_ConfigureEndpoints(&Speaker_Audio_Interface))) LEDs_SetAllLEDs(LEDMASK_USB_ERROR); } void EVENT_USB_UnhandledControlPacket(void) { USB_Audio_ProcessControlPacket(&Speaker_Audio_Interface); }