output.c

基于EP7312的MP3播放器源代码,包括MCU和PC端代码.

    //
    return(sOutput.pOutputBuffer);
}

//****************************************************************************
//
// OutputSetFormat sets the sample rate and number of channels of the input
// data stream.
//
//****************************************************************************
unsigned long
OutputSetFormat(long lSampleRate, long lChannels)
{
    BufferState *psBuffer;
    long lBaseRate;

    //
    // If the output processing interrupt is currently enabled, then turn it
    // off and wait for the output buffer to drain.
    //
    if(ulSystemFlags & SYSFLAG_PROCESS_OUTPUT)
    {
        //
        // Turn off the output processing interrupt.
        //
        DisableIRQ();
        ulSystemFlags &= ~SYSFLAG_PROCESS_OUTPUT;
        EnableIRQ();

        //
        // Wait until the the digital audio interface has completed playback.
        //
        psBuffer = DAIGetPlayBuffer();
        while(!BufferIsEmpty(psBuffer))
        {
            //
            // Put the EP7209 into HALT mode.
            //
            Halt();
        }
    }

    //
    // Determine the base rate at which to run the digital audio interface.
    //
    switch(lSampleRate)
    {
        //
        // 8000Hz, 16000Hz, and 32000Hz are played back at a base rate of
        // 32000Hz.
        //
        case 8000:
        case 16000:
        case 32000:
        {
            //
            // The base rate is 32000Hz.
            //
            lBaseRate = 32000;

            //
            // We're done with these rates.
            //
            break;
        }

        //
        // 11025Hz, 22050Hz, and 44100Hz are played back at a base rate of
        // 44100Hz.
        //
        case 11025:
        case 22050:
        case 44100:
        {
            //
            // The base rate is 44100Hz.
            //
            lBaseRate = 44100;

            //
            // We're done with these rates.
            //
            break;
        }

        //
        // 12000Hz, 24000Hz, and 48000Hz are played back at a base rate of
        // 48000Hz.
        //
        case 12000:
        case 24000:
        case 48000:
        {
            //
            // The base rate is 48000Hz.
            //
            lBaseRate = 48000;

            //
            // We're done with these rates.
            //
            break;
        }

        //
        // We assume a base rate of 44100Hz for all other sample rates.
        //
        default:
        {
            //
            // The base rate is 44100Hz.
            //
            lBaseRate = 44100;

            //
            // We're done with this rate.
            //
            break;
        }
    }

    //
    // Set the sample rate of the base rate buffer.
    //
    if(BufferSetSampleRate(sOutput.pBaseRateBuffer, lBaseRate,
                           lSampleRate) == 0)
    {
        //
        // We could not set the sample rate to the given base rate, so assume
        // a base rate of 44100Hz.
        //
        lBaseRate = 44100;

        //
        // Set the sample rate of the base rate buffer.
        //
        BufferSetSampleRate(sOutput.pBaseRateBuffer, lBaseRate, lSampleRate);
    }

    //
    // See if the sample rate is the base rate.
    //
    if(lSampleRate == lBaseRate)
    {
        //
        // Since the sample rate is the base rate, we do not need to perform a
        // sample rate conversion.  Therefore, our output buffer is the base
        // rate input buffer.
        //
        sOutput.pOutputBuffer = sOutput.pBaseRateBuffer;
    }
    else
    {
        //
        // The sample rate is not the base rate, so initialize the sample rate
        // converter.
        //
        if(SRCInit(&(sOutput.sSRC), lSampleRate, lBaseRate) == 0)
        {
            //
            // We could not initialize the sample rate converter, so return an
            // error.
            //
            return(0);
        }

        //
        // Our output buffer is the sample rate converter's input buffer.
        //
        sOutput.pOutputBuffer = SRCGetInputBuffer(&(sOutput.sSRC));

        //
        // Set the buffer for the output from the SRC.
        //
        if(lChannels == 2)
        {
            BufferSetBuffer(sOutput.pBaseRateBuffer, sOutput.sOutputLeft,
                            sOutput.sOutputRight, 384);
        }
        else
        {
            BufferSetBuffer(sOutput.pBaseRateBuffer, sOutput.sOutputLeft,
                            sOutput.sOutputLeft, 384);
        }

        //
        // If the output is enabled, then we need to enable the output
        // processing interrupt.
        //
        if(ulSystemFlags & SYSFLAG_OUTPUT_ENABLED)
        {
            DisableIRQ();
            ulSystemFlags |= SYSFLAG_PROCESS_OUTPUT;
            EnableIRQ();
        }
    }

    //
    // Success.
    //
    return(1);
}

//****************************************************************************
//
// OutputSetTone adjusts the tone controls.
//
//****************************************************************************
void
OutputSetTone(long lTreble, long lBass, long lGain)
{
#ifdef SOFTWARE_TONE_CONTROL
    //
    // Disable the IRQ interrupt.
    //
    DisableIRQ();

    //
    // Adjust the tone controls.
    //
    ToneAdjust(&(sOutput.sTone), lTreble, lBass, lGain);

    //
    // Re-enable the IRQ interrupt.
    //
    EnableIRQ();
#endif

#ifdef ADDR_CS43L43
    //
    // If the treble boost is out of range, then adjust it.
    //
    if(lTreble < 0)
    {
        lTreble = 0;
    }
    else if(lTreble > 12)
    {
        lTreble = 12;
    }

    //
    // If the bass boost is out of range, then adjust it.
    //
    if(lBass < 0)
    {
        lBass = 0;
    }
    else if(lBass > 12)
    {
        lBass = 0;
    }

    //
    // Remember the new treble and bass boost settings.
    //
    sOutput.cTrebleBoost = lTreble;
    sOutput.cBassBoost = lBass;

    //
    // If the output is enabled, then write this new settings immediately.
    //
    if(ulSystemFlags & SYSFLAG_OUTPUT_ENABLED)
    {
        TwoWireWrite((unsigned long *)(HwBaseAddress + HwPortABCD),
                     (unsigned long *)(HwBaseAddress + HwDdrABCD),
                     HwPortABCD_Clock, HwPortABCD_Data, ADDR_CS43L43, 0x06,
                     (sOutput.cBassBoost << 4) | sOutput.cTrebleBoost);
    }
#endif
}

//****************************************************************************
//
// OutputSetTreble adjusts the treble tone control.
//
//****************************************************************************
void
OutputSetTreble(long lTreble)
{
#ifdef SOFTWARE_TONE_CONTROL
    //
    // Adjust the treble control.
    //
    ToneAdjustTreble(&(sOutput.sTone), lTreble);
#endif

#ifdef ADDR_CS43L43
    //
    // If the treble boost is out of range, then adjust it.
    //
    if(lTreble < 0)
    {
        lTreble = 0;
    }
    else if(lTreble > 12)
    {
        lTreble = 12;
    }

    //
    // Remember the new treble boost setting.
    //
    sOutput.cTrebleBoost = lTreble;

    //
    // If the output is enabled, then write this new settings immediately.
    //
    if(ulSystemFlags & SYSFLAG_OUTPUT_ENABLED)
    {
        TwoWireWrite((unsigned long *)(HwBaseAddress + HwPortABCD),
                     (unsigned long *)(HwBaseAddress + HwDdrABCD),
                     HwPortABCD_Clock, HwPortABCD_Data, ADDR_CS43L43, 0x06,
                     (sOutput.cBassBoost << 4) | sOutput.cTrebleBoost);
    }
#endif
}

//****************************************************************************
//
// OutputSetBass adjusts the bass tone control.
//
//****************************************************************************
void
OutputSetBass(long lBass)
{
#ifdef SOFTWARE_TONE_CONTROL
    //
    // Adjust the bass control.
    //
    ToneAdjustBass(&(sOutput.sTone), lBass);
#endif

#ifdef ADDR_CS43L43
    //
    // If the bass boost is out of range, then adjust it.
    //
    if(lBass < 0)
    {
        lBass = 0;
    }
    else if(lBass > 12)
    {
        lBass = 0;
    }

    //
    // Remember the new bass boost setting.
    //
    sOutput.cBassBoost = lBass;

    //
    // If the output is enabled, then write this new settings immediately.
    //
    if(ulSystemFlags & SYSFLAG_OUTPUT_ENABLED)
    {
        TwoWireWrite((unsigned long *)(HwBaseAddress + HwPortABCD),
                     (unsigned long *)(HwBaseAddress + HwDdrABCD),
                     HwPortABCD_Clock, HwPortABCD_Data, ADDR_CS43L43, 0x06,
                     (sOutput.cBassBoost << 4) | sOutput.cTrebleBoost);
    }
#endif
}

//****************************************************************************
//
// OutputSetGain adjusts the gain control.
//
//****************************************************************************
void
OutputSetGain(long lGain)
{
#ifdef SOFTWARE_TONE_CONTROL
    //
    // Adjust the gain control.
    //
    ToneAdjustGain(&(sOutput.sTone), lGain);
#endif
}

//****************************************************************************
//
// OutputToneEnable enables the software tone control.
//
//****************************************************************************
#ifdef SOFTWARE_TONE_CONTROL
void
OutputToneEnable(void)
{
    //
    // Enable the tone control.
    //
    ToneEnable(&(sOutput.sTone));
}
#endif

//****************************************************************************
//
// OutputToneDisable disables the software tone control.
//
//****************************************************************************
#ifdef SOFTWARE_TONE_CONTROL
void
OutputToneDisable(void)
{
    //
    // Disable the tone control.
    //
    ToneDisable(&(sOutput.sTone));
}
#endif

//****************************************************************************
//
// OutputSetVolume adjusts the volume control.
//
//****************************************************************************
void
OutputSetVolume(long lGain)
{
#ifdef SOFTWARE_VOLUME_CONTROL
    //
    // Adjust the volume control.
    //
    VolumeAdjust(&(sOutput.sVolume), lGain);
#endif

#ifdef ADDR_CS43L43
    //
    // If the volume setting is out of range, then adjust it.
    //
    if(lGain < 0)
    {
        lGain = 0;
    }
    else if(lGain > 20)
    {
        lGain = 20;