; C/MS chip programming example
;
; Plays middle C note
;
; Written by JDA of Elastic Force, 1991.
; Based on not-working piece of code from Creative Labs.
; (does this work ??)
DOSSEG
.MODEL MEDIUM
.STACK 200h
.CODE
; initialize voice 1-6
MOV DX,221H ; Address register for channels 1-6
MOV AL,0 ; start with register address 0
LABEL1:
OUT DX,AL ; Select internal register
MOV AH,DL ; preserve register address to AH
DEC DX ; point to data register, 220h
SUB AL,AL ; Zero AL by subtracting it with itself.
OUT DX,AL ; Send to port
INC DX ; point to address register, 221h
MOV AL,AH ; recover register address from AH
INC AL ; move to next address
CMP AL,20H ; Compare AL with 20h
JB Label1 ; If less, jump to LABEL1
MOV AL,1CH ; select frequency reset register
OUT DX,AL ; for all channels
DEC DX ; Point to data register 220h
MOV AL,2 ; Register address 2
OUT DX,AL ; Reset frequency for voice #1-6
;--initial voice#7-12
MOV DX,223H ; Address register for channels 7-12
MOV AL,0 ; Register address 0
LABEL2: OUT DX,AL ; Select internal register
MOV AH,AL ; Preserve register address to AH
DEC DX ; Point to data register 222h
SUB AL,AL ; Zero AL
OUT DX,AL ; Initialize to 0
INC DX ; Point to address register 223h
MOV AL,AH ; Recover regs. address from AH
INC AL ; Move to next address
CMP AL,20H ; Compare AL with 20h
JB LABEL2 ; Jump if Below.
MOV AL,1CH ; Select frequency reset register
OUT DX,AL ; for all channels
DEC DX ; Point to data port 222h
MOV AL,2
OUT DX,AL ; Reset frequency for voice#7-12
;Following codes enable sound for all voices :
MOV DX,221H ; Channels 1-6 register port 221h
MOV AL,1CH ; Sound enable register, 1C,
OUT DX,AL ; Select sound enable register
DEC DX ; Channels 1-6 data port 220h
MOV AL,1 ; Registers address 1
OUT DX,AL ; Select all sound for voice#1-6
MOV DX,223H ; Channels 7-12 register port 223h
MOV AL,1CH ; Sound/Frequency enable register
OUT DX,AL ; Select sound enable register
DEC DX ; Point to data port 222h
MOV AL,1 ; Register address 1
OUT DX,AL ; enable all sound for voice#7-12
;Following codes output music note middle C to voice#1 :
MOV DX,221H ; address register for voices 1-6
; Program the amplitude
MOV AL,0
OUT DX,AL ; select internal amplitude registers
DEC DX ; point to data port 220h
MOV AL,3AH ; left amplitude 10, right amplitude 3
; Program the frequency
INC DX ; point to address port 221h
MOV AL,8 ; frequency of tone 1/7
OUT DX,AL ; select internal frequency registers
DEC DX ; point to data port 220h
MOV AL,83 ; frequency value for middle C
OUT DX,AL ; send it to port
; Program the octave
INC DX ; point to register port 221h
MOV AL,10H ; octave 2/8; octave 1/7
OUT DX,AL ; select internal octave registers
DEC DX ; point to data port 220h
MOV AL,03H ; octave value 3 (middle C) for voice #1
OUT DX,AL ; Send it to 220h
;frequency enable
INC DX ; point to address port 221h
MOV AL,14H ; frequency enable
OUT DX,AL ; select internal octave registers
DEC DX ; point to data port 220h
MOV AL,01H ; enable voice# 1 frequency
OUT DX,AL ; send to 220h.
;quit
MOV AX,4CH
INT 21h
END
