demillo@uwmacc.UUCP (Rob DeMillo) (11/12/85)
I find myself in need of some help. Can anyone out there point
me in there direction of finding a reference? I am trying to
access the speaker of my XT via assmebly language routines, and
I am having a devil of a time. Any magazine or journal references
that you might recommend?
Thanks in advance.
--
--- Rob DeMillo
Madison Academic Computer Center
...seismo!uwvax!uwmacc!demillo
"...I suppose you think the concept of a
robot with an artificial leg is amusing?"
-- Marvin, the Paranoid Android
vch@rruxo.UUCP (Kerro Panille) (11/19/85)
>I find myself in need of some help. Can anyone out there point >me in there direction of finding a reference? I am trying to >access the speaker of my XT via assmebly language routines, and >I am having a devil of a time. Any magazine or journal references >that you might recommend? The speaker is accessed by a port number - use the IN and OUT instructions to access it. I don't know exactly what port it is, but it should be in the IBM Technical Reference Manual. Peter Norton has a few sample assembler programs in his book, Inside The IBM PC. Chapter 3, listing 3.2. Norton also goes into a little detail as to how this works. Here it is, the speaker port is number 61 (hex). Inside The IBM PC is a good book for beginners - it does not go into great detail, but should be sufficient for most simple tasks. Buy an assembly language book for more details. Manuals also help. -- Vince Hatem ---------------- A Bell Communications Research | UZI |----------|_ _ _\/ T Raritan River Software Systems Center | |----------| /\ & 444 Hoes Lane ---------------- ROGER GUTS T 4D-360 / /\ DON'T NEED NO STINKIN' Piscataway, NJ 08854 / / NECKTIES (201) 699-4869 /-----/ ...ihnp4!rruxo!vch TRUE GRIT MYSTERIES - The detective series for those who NEVER eat quiche! (WARNING - MAY BE EMOTIONALLY DISTURBING TO HAMSTER LOVERS)
mjm@cantor.UUCP (Michael Markowitz) (11/21/85)
> > >... I am trying to > >access the speaker of my XT via assmebly language routines, and > >I am having a devil of a time. Any magazine or journal references > >that you might recommend? > > The speaker is accessed by a port number - use the IN and OUT instructions > to access it. I don't know exactly what port it is, but it should be in the > IBM Technical Reference Manual. Peter Norton has a few sample assembler > programs in his book, Inside The IBM PC. Chapter 3, listing 3.2. Norton > also goes into a little detail as to how this works. Here it is, the > speaker port is number 61 (hex). > First of all, port 61H is port B of the 8255A-5 PPI (programmable peripheral interface). If you start OUT'ing indescriminant data to that port you are probably going to disable your keyboard and parity checking--although you might get the speaker to go on at the same time! Actually you enable the ouput of timer channel 2 (which is fed to the speaker) by writing a 1 to bit 0 of this port. Bit 1 may be used to turn the speaker on and off. To get a specific frequency to sound you must program counter 2 of the timer. Try the following as an example (there are other ways to do this): middle_C dw 262 ;261.6 Hz mov al,0B6H ;select channel 2, mode 3 (square wave) out 43H,al ; send to timer (order 16-bit read) mov ax,34dcH ;calculate initial count (1.193MHz/262Hz) mov dx,12H div middle_C out 42H,al ;send LSB to counter 2 mov al,ah out 42H,al ; then send MSB in al,61H ;read data latched in output port B of PPI or al,3 ;enable timer channel 2 output and speaker out 61H,al ;send back to PPI (don't mess with other bits) mov bx,???? ;you'll have to choose appropriate values again: mov cx,???? ; here to generate the desired delay play: loop play ;(off the top of my head I estimate 64K dec bx ;iterations will give you .2 seconds on a PC) jnz again ;(this is using a bx=1, cx=0) in al,61H ;(this is redundant, status is already in AL!) xor al,3 ;disable timer channel 2 output and speaker out 61H,al ;have PPI turn off that damn noise! Hope this helps. Michael Markowitz Dept. of Math. Sciences Loyola Univ. of Chicago Chicago, IL 60626 ihnp4!gargoyle!cantor!able!mjm