64 lines
1.9 KiB
ArmAsm
64 lines
1.9 KiB
ArmAsm
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;=====================
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;=====================
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;=====================
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; ay3 write regs
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;=====================
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;=====================
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;=====================
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; write all 13 registers
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; address in X
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; data in A
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ay3_write_regs:
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ldx #13
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ay3_write_reg_loop:
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lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
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ldy #MOCK_AY_INACTIVE ; go inactive ; 2
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stx MOCK_6522_ORA1 ; put address on PA1 ; 4
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sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
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sty MOCK_6522_ORB1 ; 4
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; value
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lda $70,X
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sta MOCK_6522_ORA1 ; put value on PA1 ; 4
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lda #MOCK_AY_WRITE ; ; 2
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sta MOCK_6522_ORB1 ; write on PB1 ; 4
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sty MOCK_6522_ORB1 ; 4
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dex
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bpl ay3_write_reg_loop
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rts
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; starts at C4
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frequency_lookup_low:
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.byte $E8,$CD,$B3,$9B,$83,$6E,$59,$46,$33,$22,$12,$02
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;$1E8,$1CD,$1B3,$19B,$183,$16E,$159,$146,$133,$122,$112,$102,
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;.byte $F4,$E6,$D9,$CD,$C1,$B7,$AC,$A3,$99,$91,$89,$81,$00,$00,$00,$00
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;.byte $7A,$73,$6C,$66,$60,$5B,$56,$51,$4C,$48,$44,$40,$00,$00,$00,$00
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;.byte $3D,$39,$36,$33,$30,$2D,$2B,$28,$26,$24,$22,$20,$00,$00,$00,$00
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init_addresses:
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.byte <MOCK_6522_DDRB1,<MOCK_6522_DDRA1 ; set the data direction for all pins of PortA/PortB to be output
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.byte <MOCK_6522_ACR,<MOCK_6522_IER ; Continuous interrupts, clear all interrupts
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.byte <MOCK_6522_IFR,<MOCK_6522_IER ; enable interrupt on timer overflow
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.byte <MOCK_6522_T1CL,<MOCK_6522_T1CH ; set oflow value, start counting
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.byte <MOCK_6522_ORB1,<MOCK_6522_ORB1 ; reset ay-3-8910
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; note, terminated by the $ff below
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init_values:
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.byte $ff,$ff ; set the data direction for all pins of PortA/PortB to be output
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.byte $40,$7f
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.byte $C0,$C0
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.byte $CE,$C7 ; c7ce / 1.023e6 = .050s, 20Hz
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.byte MOCK_AY_RESET,MOCK_AY_INACTIVE
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