CC3200AUDBOOST: Wrong threshold level in AudioCodec_speakerVolCtrl (AudioCodec.c)

Hi everyone,

I just found a small mistake in the file AudioCodec.c which is part of the example programs for the CC3200 Audio BoosterPack:

When you ramp up the output volume of the TLV320AIC3254 codec from 0 to 100 using the function AudioCodec_speakerVolCtrl, you expect a volume increase by 1dB from step to step. However, you will notice two volume level steps, where the volume increases/decreases by much more than 1dB. This is because the threshold for clipping the level to +24dB is set to 97 instead of 91. The correct code looks like this (I added some additional comments to the code):

int AudioCodec_speakerVolCtrl(unsigned char codecId, unsigned char speaker, signed char volumeLevel)

{

    short  vol = 0;

    if(volumeLevel < 4)

    { // volumeLevel < 4: mute

        vol = 0x80;

    }

    else if (volumeLevel > 91)  // original value of 97 is too large!

    { // volumeLevel > 91: +24dB

        vol = 0x30;

    }

    else

    { // 4 <= volumeLevel <= 91

        vol = 122 + (volumeLevel << 1);

    }

    AudioCodec_pageSelect(TI3254_PAGE_0);

    AudioCodec_regWrite(TI3254_LEFT_DAC_VOL_CTRL_REG, (unsigned char )(vol&0x00FF));

    AudioCodec_regWrite(TI3254_RIGHT_DAC_VOL_CTRL_REG, (unsigned char )(vol&0x00FF));

    return 0;

}

Dear TI-Engineers: Please correct the number for the next release of the demo programs. Thank you.

P.S.:

This may be a simple typo or (more likely) the misunderstood hand writing of i.e. a German who uses to write the '1' like this . This looks very similar to the 7. Engineers should better know that when working together with Germans ;-)

I changed my hand writing because of this and use 'I' instead of '1' when working in international teams. (I am a German engineer.)