Sounds, sounds, sounds..

 BBS: Inland Empire Archive
Date: 07-09-92 (21:38)             Number: 85
From: STEVE HALKO                  Refer#: NONE
  To: PHIL HODGES                   Recvd: NO  
Subj: Sounds, sounds, sounds..       Conf: (2) Quik_Bas

PH>SOUND..since it's way to limiting. I want to be able to specify
PH>frequency, velocity (the rate of change), acceleration (the rate of the
PH>rate of change) and duration.

  This might give you a start, Phil.  It's what I use as a replacement
  for the SOUND statement to keep the FP emulator out of my programs.
  The arguments are frequency (in Hz), and duration (in clock ticks):


  SUB Sounds (Freq, Length) STATIC

  'Ports 42h, 43h, and 61h control timer and speaker
  '
  'Divide clock frequency by sound frequency
  'to get number of "clicks" clock must produce
      Clicks = 1193280 \ Freq
      LoByte = Clicks AND &HFF
      HiByte = Clicks \ 256
  'Tell timer that data is coming
      OUT &H43, 182
  'Send count to timer
      OUT &H42, LoByte
      OUT &H42, HiByte
  'Turn speaker on by setting bits 0 and 1 of PPI chip.
      SpkrOn = INP(&H61) OR &H3
      OUT &H61, SpkrOn
  'Leave speaker on
      StopTime& = ReadTimer& + Length
      DO WHILE ReadTimer& < StopTime&
      LOOP
  'Turn speaker off.
      SpkrOff = INP(&H61) AND &HFC
      OUT &H61, SpkrOff

  END SUB

  FUNCTION ReadTimer& STATIC

   '[]=============================================================[]
   '[]   Returns the number of clock ticks since midnight          []
   '[]   without invoking FP emulator like TIMER does              []
   '[]=============================================================[]

     DEF SEG = &H40
     Lo& = PEEK(&H6C) + 256& * PEEK(&H6D)
     Hi& = PEEK(&H6E) + 256& * PEEK(&H6F)


     ReadTimer& = (65536 * Hi&) + Lo&

  END FUNCTION

 * SLMR 2.1a * If you don't eat your meat, you can't have any pudding!

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