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prodos-drivers
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Add Cricket detection. Resolves #3

This commit is contained in:
Joshua Bell 2017-11-29 19:08:07 -08:00
parent 381b9ddf54
commit 7b45ae144e
2 changed files with 98 additions and 29 deletions
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112
cricket.system.s
View File

@ -151,52 +151,120 @@ cloop: iny
.endproc
;;; ------------------------------------------------------------
;;; Detect Cricket.
;;; TODO: Implement this!
;;; Detect Cricket. Detect SSC and if present probe device.
.proc detect_cricket
;; Preserve date/time
ldy #3 ; copy 4 bytes
: lda DATELO,y
sta saved,y
dey
bpl :-
;; Check Slot 2 for SSC. ID bytes per:
;; Apple II Technical Note #8: Pascal 1.1 Firmware Protocol ID Bytes
lda $C205
cmp #$38
bne not_found
bne ssc_not_found
lda $C207
cmp #$18
bne not_found
bne ssc_not_found
lda $C20B
cmp #$01
bne not_found
bne ssc_not_found
lda $C20C
cmp #$31
bne not_found
bne ssc_not_found
;; TODO: Write NUL and check for 'C' ... version ... $8D (CR)
;; https://github.com/inexorabletash/cricket/issues/3
beq init_ssc
ssc_not_found:
jmp not_found
;; Init SSC and try the "Read Cricket ID code" sequence.
init_ssc:
lda COMMAND ; save status of SSC registers
sta saved_command
lda CONTROL
sta saved_control
;; Configure SSC
lda #%00001011
sta COMMAND
lda #%10011110 ; 9600 baud, 8 data bits, 2 stop bits
sta CONTROL
;; Read Cricket ID code: 00 ($00)
lda #0
jsr sendbyte
;; "The Cricket will return a "C" (195, $C3) followed by a
;; version number (in ASCII) and a carriage return (141, $8D)."
jsr readbyte
bcs cricket_not_found ; timeout
cmp #HI('C') ; = 'C' ?
bne cricket_not_found
: jsr readbyte
bcs cricket_not_found ; timeout
cmp #HI(CR) ; = CR ?
beq cricket_found ; TODO: Require digits between 'C' and CR
cmp #HI('0') ; < '0' ?
bcc cricket_not_found
cmp #HI('9' + 1) ; > '9' ?
bcs cricket_not_found
bcc :-
cricket_found:
jmp install_driver
;; If not found, restore date/time
not_found:
ldy #3
: lda saved,y
sta DATELO,y
dey
bpl :-
cricket_not_found:
lda saved_control
sta CONTROL
lda saved_command
sta COMMAND
;; fall through...
not_found:
;; Show failure message
jsr MON_HOME
jsr zstrout
HIASCIIZ CR, CR, CR, PRODUCT, " - Not Found."
jmp launch_next_sys_file
saved: .byte 0, 0, 0, 0
saved_command: .byte 0
saved_control: .byte 0
.endproc
;; Write byte in A
.proc sendbyte
pha
: lda STATUS
and #(1 << 4) ; transmit register empty? (bit 4)
beq :- ; nope, keep waiting
pla
sta TDREG
rts
.endproc
;; Read byte into A, or carry set if timed out
.proc readbyte
tries := $300
counter := $A5
lda #<tries
sta counter
lda #>tries
sta counter+1
check: lda STATUS ; did we get it?
and #(1 << 3) ; receive register full? (bit 3)
bne ready ; yes, we read the value
dec counter
bne check
dec counter+1
bne check
sec ; failed
rts
ready: lda RDREG ; actually read the register
clc
rts
.endproc
;;; ------------------------------------------------------------

15
test.s
View File

@ -112,10 +112,12 @@ saved_control: .byte 0
;; Read byte into A, or carry set if timed out
.proc readbyte
tries := $300
lda #<tries
sta counter
lda #>tries
sta counter+1
counter := $A5
lda #<tries
sta counter
lda #>tries
sta counter+1
check: lda STATUS ; did we get it?
and #(1 << 3) ; receive register full? (bit 3)
@ -129,10 +131,9 @@ check: lda STATUS ; did we get it?
sec ; failed
rts
ready: clc
ready: lda RDREG ; actually read the register
clc
rts
counter: .word 0
.endproc