[A83] Re: help with sound


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[A83] Re: help with sound





----- Original Message -----
From: "Charlie Adams" <charlie_w_adams@yahoo.com>
To: <assembly-83@lists.ticalc.org>
Sent: Sunday, January 27, 2002 2:12 PM
Subject: [A83] help with sound
oops, i meant until you press 2nd or Clear, enter doesn't work wuth
bcall(_getk)

> ok, i found a sound routine in the old sos lib, but i don't understand how
it works with the frequency.  this code beeps until you press enter, but how
does it know what frequency?
> start:
>     ld  c,69 ;c is the frequency
>     ld  b,255 ;b is the duration
> beep:   di ;disable interrupts
>     ld  e,$D0
> beepl1: ld  a,c
> beepl2: dec a
>     jr  nz,beepl2
>     ld  a,e
>     xor %00000011
>     ld  e,a
>     out (0),a
>     djnz    beepl1
>     ei
>     bcall(_getk)
>     jp  z,start
>     ret
> .end
> END
>


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