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101 lines
2.4 KiB
101 lines
2.4 KiB
;
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;======================================================================
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; PSG AY-3-8910 DRIVER FOR CONSOLE BELL
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; WILL ALSO WORK WITH YM2149
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;======================================================================
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;
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AY_RSEL .EQU $9A
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AY_RDAT .EQU $9B
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AY_ACR .EQU $9C
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AY_R0CHAP .EQU $00
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AY_R1CHAP .EQU $01
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AY_R2CHBP .EQU $02
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AY_R3CHBP .EQU $03
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AY_R7ENAB .EQU $07
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AY_R8AVOL .EQU $08
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AY_R9BVOL .EQU $09
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;
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;======================================================================
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; PSG AY-3-8910 DRIVER - INITIALIZATION
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;======================================================================
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;
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AY_INIT:
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CALL NEWLINE ; FORMATTING
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PRTS("AY: IO=0x$")
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LD A,AY_RSEL
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CALL PRTHEXBYTE
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CALL AY_PROBE ; CHECK FOR HW EXISTENCE
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JR Z,AY_INIT1 ; CONTINUE IF PRESENT
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;
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; HARDWARE NOT PRESENT
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;
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PRTS(" NOT PRESENT$")
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OR $FF ; SIGNAL FAILURE
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RET
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;
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AY_INIT1:
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CALL AY_INIT2
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CALL AY_BEEP
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AY_INIT2:
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LD D,AY_R7ENAB ; SET MIXER CONTROL / IO ENABLE
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LD E,$FF ; $FF - 11 111 111
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CALL AY_WRTPSG ; I/O PORTS DISABLED, NOISE CHANNEL C, B, A DISABLE, TONE CHANNEL C, B, A DISABLE
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;
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LD B,2
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LD D,AY_R8AVOL ; SET VOLUME TO 0
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LD E,$00
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AY_QUIET:
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CALL AY_WRTPSG ; CYCLING THROUGH ALL CHANNELS
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INC A
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DJNZ AY_QUIET
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RET
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;
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; PLAY A BEEP TONE ON CENTER CHANNEL (LEFT AND RIGHT SPEAKERS)
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;
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AY_BEEP:
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LD D,AY_R2CHBP ; SET TONE PERIOD
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LD E,$55 ; CHANNEL B - R00 & R01
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CALL AY_WRTPSG ; $0055 = XXXX0000 01010101
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LD D,AY_R3CHBP
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LD E,0
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CALL AY_WRTPSG
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;
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LD D,AY_R7ENAB ; $FD = 11 111 101
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LD E,$FD ; SET MIXER CONTROL / IO ENABLE
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CALL AY_WRTPSG ; I/O PORTS DISABLED, NOISE CHANNEL C, B, A DISABLE, TONE CHANNEL B ENABLE
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;
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LD D,AY_R9BVOL
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LD E,$07 ; SET CHANNEL B VOLUME TO 50% (7/16)
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CALL AY_WRTPSG
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;
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CALL LDELAY ; HALF SECOND
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RET
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;
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; WRITE DATA E TO PSG REG A
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;
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AY_WRTPSG:
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HB_DI
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#IF ((PLATFORM == PLT_N8) | (PLATFORM == PLT_MK4) | (PLATFORM == PLT_RC180))
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IN0 A,(Z180_DCNTL) ; GET WAIT STATES
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PUSH AF ; SAVE VALUE
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OR %00110000 ; FORCE SLOW OPERATION (I/O W/S=3)
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OUT0 (Z180_DCNTL),A ; AND UPDATE DCNTL
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#ENDIF
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LD A,D
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OUT (AY_RSEL),A
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LD A,E
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OUT (AY_RDAT),A
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#IF ((PLATFORM == PLT_N8) | (PLATFORM == PLT_MK4) | (PLATFORM == PLT_RC180))
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POP AF ; GET SAVED DCNTL VALUE
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OUT0 (Z180_DCNTL),A ; AND RESTORE IT
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#ENDIF
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HB_EI
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RET
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;
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; CHECK THERE IS A DEVICE PRESENT
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;
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AY_PROBE:
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LD A,$FF
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OUT (AY_ACR),A ; INIT AUX CONTROL REG
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XOR A
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RET
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