dos33fsprogs/music/tiny_tracker5/mockingboard_init.s
2022-01-18 23:53:24 -05:00

78 lines
2.3 KiB
ArmAsm

; Mockingboad programming:
; + Has two 6522 I/O chips connected to two AY-3-8910 chips
; + Optionally has some speech chips controlled via the outport on the AY
; + Often in slot 4
; TODO: how to auto-detect?
; References used:
; http://macgui.com/usenet/?group=2&id=8366
; 6522 Data Sheet
; AY-3-8910 Data Sheet
;========================
; Mockingboard card
; Essentially two 6522s hooked to the Apple II bus
; Connected to AY-3-8910 chips
; PA0-PA7 on 6522 connected to DA0-DA7 on AY
; PB0 on 6522 connected to BC1
; PB1 on 6522 connected to BDIR
; PB2 on 6522 connected to RESET
; left speaker
MOCK_6522_ORB1 = $C400 ; 6522 #1 port b data
MOCK_6522_ORA1 = $C401 ; 6522 #1 port a data
MOCK_6522_DDRB1 = $C402 ; 6522 #1 data direction port B
MOCK_6522_DDRA1 = $C403 ; 6522 #1 data direction port A
MOCK_6522_T1CL = $C404 ; 6522 #1 t1 low order latches
MOCK_6522_T1CH = $C405 ; 6522 #1 t1 high order counter
MOCK_6522_T1LL = $C406 ; 6522 #1 t1 low order latches
MOCK_6522_T1LH = $C407 ; 6522 #1 t1 high order latches
MOCK_6522_T2CL = $C408 ; 6522 #1 t2 low order latches
MOCK_6522_T2CH = $C409 ; 6522 #1 t2 high order counters
MOCK_6522_SR = $C40A ; 6522 #1 shift register
MOCK_6522_ACR = $C40B ; 6522 #1 auxilliary control register
MOCK_6522_PCR = $C40C ; 6522 #1 peripheral control register
MOCK_6522_IFR = $C40D ; 6522 #1 interrupt flag register
MOCK_6522_IER = $C40E ; 6522 #1 interrupt enable register
MOCK_6522_ORANH = $C40F ; 6522 #1 port a data no handshake
; right speaker
MOCK_6522_ORB2 = $C480 ; 6522 #2 port b data
MOCK_6522_ORA2 = $C481 ; 6522 #2 port a data
MOCK_6522_DDRB2 = $C482 ; 6522 #2 data direction port B
MOCK_6522_DDRA2 = $C483 ; 6522 #2 data direction port A
; AY-3-8910 commands on port B
; RESET BDIR BC1
MOCK_AY_RESET = $0 ; 0 0 0
MOCK_AY_INACTIVE = $4 ; 1 0 0
MOCK_AY_READ = $5 ; 1 0 1
MOCK_AY_WRITE = $6 ; 1 1 0
MOCK_AY_LATCH_ADDR = $7 ; 1 1 1
;========================
;========================
; Mockingboard Init
;========================
;========================
; Left channel only
mockingboard_init:
;=========================
; Initialize the 6522s
; Reset Left AY-3-8910
;===========================
ldx #$FF
stx MOCK_6522_DDRB1
stx MOCK_6522_DDRA1
inx ; #MOCK_AY_RESET $0
stx MOCK_6522_ORB1
ldx #MOCK_AY_INACTIVE ; $4
stx MOCK_6522_ORB1