mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-11-16 23:20:43 +00:00
140 lines
2.7 KiB
ArmAsm
140 lines
2.7 KiB
ArmAsm
; This code detects a SSI263 chip on a Mockingboard
|
|
; it does this by trying to enable the chip and waiting for
|
|
; the SSI-263 to signal an interrupt when done.
|
|
; If the interrupt never comes then assume no SSI-263 is present
|
|
; The code assumes the SSI-263 is hooked to VIA6522 #2 (?)
|
|
|
|
;=============================
|
|
;=============================
|
|
; detect SSI263
|
|
;=============================
|
|
;=============================
|
|
; A = slot of mockingboard
|
|
; carry set if found
|
|
|
|
detect_ssi263:
|
|
and #$7
|
|
ora #$c0 ; turn slot number into address
|
|
sta ssid_wc_smc1+2 ; update the read/write routines
|
|
|
|
sei ; disable IRQ
|
|
|
|
lda $3fe ; backup the IRQ handler
|
|
sta irq1backup
|
|
lda $3ff
|
|
sta irq2backup
|
|
|
|
lda #<mb_irq ; point IRQ handler to our code
|
|
sta $3fe
|
|
lda #>mb_irq
|
|
sta $3ff
|
|
|
|
; Set 6522#2 peripheral control register to recognize the signal
|
|
; from the speech chip.
|
|
lda #(VIA6522_PCR2_CA2_LOW|VIA6522_PCR2_CA1_NEG)
|
|
ldx #VIA6522_PCR2
|
|
jsr ssi263_d_write_chip
|
|
|
|
; Raise control bit in register 3 of SSI-263
|
|
lda #SSI263_CAA_CTL
|
|
ldx #SSI263_CAA
|
|
jsr ssi263_d_write_chip
|
|
|
|
; Transitioned inflection (when CTL is toggled)
|
|
lda #SSI263_DRP_TRANSITIONED_INFLECTION
|
|
ldx #SSI263_DRP
|
|
jsr ssi263_d_write_chip
|
|
|
|
; Lower control bit in SSI-263
|
|
lda #$70 ; CTL=0, T=6, AMP=0
|
|
ldx #SSI263_CAA
|
|
jsr ssi263_d_write_chip
|
|
|
|
; Enable 6522 interrupt on input CA2
|
|
lda #(VIA6522_IER2_SET|VIA6522_IER2_CA1)
|
|
ldx #VIA6522_IER2
|
|
jsr ssi263_d_write_chip
|
|
|
|
ldx #0 ; clear counts
|
|
ldy #0
|
|
|
|
cli ; enable interrupts
|
|
|
|
wait_irq:
|
|
lda irq_count ; see if irq happened
|
|
|
|
bne got_irq
|
|
|
|
iny ; otherwise increase counts
|
|
bne wait_irq
|
|
inx ;
|
|
bne wait_irq
|
|
sei
|
|
clc ; not found
|
|
rts
|
|
|
|
got_irq:
|
|
sei ; disable interrupts
|
|
sec ; found
|
|
|
|
rts
|
|
|
|
|
|
;========================
|
|
; detection IRQ handler
|
|
;========================
|
|
mb_irq:
|
|
txa ; save X
|
|
pha
|
|
|
|
; Clear the 6522 interrupt flag
|
|
lda #VIA6522_IFR2_CA1
|
|
ldx #VIA6522_IFR2
|
|
jsr ssi263_d_write_chip
|
|
|
|
; disable speech
|
|
|
|
; Raise control bit in register 3 of SSI-263
|
|
lda #SSI263_CAA_CTL
|
|
ldx #SSI263_CAA
|
|
jsr ssi263_d_write_chip
|
|
|
|
; Disable talking on SSI-263 (when CTL is toggled)
|
|
lda #SSI263_DRP_DISABLE_AR
|
|
ldx #SSI263_DRP
|
|
jsr ssi263_d_write_chip
|
|
|
|
; Lower control bit in SSI-263
|
|
lda #$70 ; also T=7?
|
|
ldx #SSI263_CAA
|
|
jsr ssi263_d_write_chip
|
|
|
|
; increment our irq count
|
|
|
|
inc irq_count
|
|
|
|
; Disable 6522 interrupts
|
|
lda #VIA6522_IER2_CA1
|
|
ldx #VIA6522_IER2
|
|
jsr ssi263_d_write_chip
|
|
|
|
pla ; restore X
|
|
tax
|
|
|
|
lda $45 ; restore accumulator
|
|
|
|
rti ; return from interrupt
|
|
|
|
|
|
;========================
|
|
; write_chip
|
|
;========================
|
|
ssi263_d_write_chip:
|
|
ssid_wc_smc1:
|
|
sta $C000,X
|
|
rts
|
|
|
|
irq_count: .byte $00
|
|
irq1backup: .byte $00
|
|
irq2backup: .byte $00
|