Piezo Audio - Part 3 of 9

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3 - A Single Tone to Start

First off we'll look at individual tone generation:

  void piezo_play_1tone(struct piezo_tone t, int flags);

The flags represent how tones are handled, and can be zero or any of the following:

PIEZO_FLAG_WAIT - Queue up the tone to play after the current one finishes. Note however that the function returns immediately.
PIEZO_FLAG_4EVER - Repeatedly play tone(s).
PIEZO_FLAG_NOQUIET - Play even if volume of the ebm has been turned down or off (quiet mode). Can be combined with the other flags.

If zero is passed then the note plays a single time, and can be immediately preempted by another piezo play call. Of course, there are times you want to stop the tone without playing another one; for this use the macro piezo_stop().

The first parameter to the call is the piezo_tone structure, which looks like this:

  struct piezo_tone
  { 
    unsigned char tone;
    unsigned char man;
    unsigned char exp;
    unsigned char unused; // always set to zero
  };

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