chris/open-roms
1
0 Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

actually try 255 times before giving up when waiting for talker turnaround.

Browse Source
This commit is contained in:
Paul Gardner-Stephen committed 2019-05-04 22:09:19 +09:30
1 parent 84841ab283
commit d0932029bb
1 file changed
+3 -7
Download Patch File Download Diff File Expand all files Collapse all files
c64/kernal/iec_turnaround_to_listen.s
+3 -7
View File
@@ -3,29 +3,25 @@
iec_turnaround_to_listen: iec_turnaround_to_listen:
jsr printf
.byte "DOING TURNAROUND",$0d,0
;; Assert data and release clock ;; Assert data and release clock
lda $dd00 lda $dd00
sta $0420 sta $0420
and #$ef ; release clock (bit 4) and #$ef ; release clock (bit 4)
ora #$20 ; assert data (bit 5) ora #$20 ; assert data (bit 5)
sta $dd00 sta $dd00
;; Wait for clock line to be asserted by the drive ;; Wait for clock line to be asserted by the drive
* lda $dd00 * lda $dd00
sta $0421 sta $0421
and #$40 and #$40
bne - bne -
;; Wait for clk to be released by the drive to mark ready to talk
ldx #$ff ldx #$ff
* lda $dd00 * lda $dd00
and #$40 and #$40
bne + bne +
dex dex
beq - bne -
jsr printf jsr printf
.byte "TURNAROUND FAILED - FILE NOT FOUND?",$0d,$00 .byte "TURNAROUND FAILED - FILE NOT FOUND?",$0d,$00