105 lines
2.7 KiB
Plaintext
105 lines
2.7 KiB
Plaintext
Some notes on programing for the Disney Sound Source.
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The Sound Source is a simple digital-to-analog sound device for the IBM PC
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type computers. It consists of two parts, a dongel that hang off the printer
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port and a 9 volt battery amplifier/speaker box.
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Since the SS is an output only device, I have to assume that you have a
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source of digital sounds to play back. Due to filtering on the SS, it works
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best with sounds sampled at less than 8Khz. This limits the sound output to
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around 4Khz, about as good as a very good phone connection.
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While Disney has been less than forthcoming about information about a
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software developers kit, writing sound output routines for the SS is fairly
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simple.
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You only have to be concerned with 3 routines.
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1. SS on.
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2. Write data to SS.
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3. SS off.
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The output rate is controlled by your program, usually by the hardware
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timer.
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To turn on the SS do the following:
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Read PrinterPort + 2 ;ControlPort
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Clear Bit 3
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Write ControlPort
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In ASM:
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SS_ON:
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MOV DX,37Ah ;Address of LPT1 control port
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IN AL,DX
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AND AL,11110111b ;Clear bit 3
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OUT DX,AL ;Turn on SS
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Turning the SS off is almost the same:
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Read ControlPort
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Set Bit 3
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Write ControlPort
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SS_OFF:
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MOV DX,37Ah
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IN AL,DX
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OR AL,00001000b ;Set bit 3
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OUT DX,AL
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Send data like this:
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Write data to PrinterPort
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Pulse Bit 3 of ControlPort
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BYTE_OUT assumes AL has the data byte to be sent to the SS and that
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the SS is on. (Bit 3 of ControlPort is off)
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BYTE_OUT:
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MOV DX,378h ;PrinterPort
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OUT DX,AL ;Send data to SS
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PULSE:
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ADD DX,2 ;Set DX to ControlPort
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IN AL,DX
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OR AL,00001000b ;Bit 3 on
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OUT DX,AL
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JMP $+2 ;short delay to settle buss
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IN AL,DX
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AND AL,11110111b ;Bit 3 off
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OUT DX,AL
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I know that these routines are fairly simple and the could be improved on.
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A close examination of the SS electronics reveals the capacity to generate
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interrupts, (set bits 2 and 4 of ControlPort to possibily enable ints)
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but I haven't gotten that far yet.
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If you have any comments, critiques, ect. I am:
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Mark Phillips
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Cserve 73167,3216
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Shameless Plug Time.
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Many thanks to Adrienne Cousins of VersaWare for her help with the above.
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Get, register, and enjoy Adrienne's SPUTTER Sound System. It handles
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Adlib, SoundBlaster, all Covox sound products, Disney SS, and the PC speaker.
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Easy to use and fun, it's the best !!!
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Search for SPUT115A, B, and C on your local BBS.
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mjp
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