more work towards physical floppy suppport

src/dos_m65/dos_imports.s

@@ -12,3 +12,5 @@
 
 ;; #ALIAS# m65_speed_tape_cbdos            = KERNAL_0.m65_speed_tape_cbdos
 ;; #ALIAS# m65_speed_restore               = KERNAL_0.m65_speed_restore
+
+;; #ALIAS# wait_x_bars                     = KERNAL_0.wait_x_bars

src/dos_m65/lowlevel/lowlevel_helpers.s

@@ -1,49 +0,0 @@
-
-; Helper routines for low-level disk operations
-
-
-lowlevel_ensure_presence:
-
-	lda FDC_STATUS_B ; $D083           ; check if disk is inserted    XXX this is probably not enough!
-	and #$08
-	beq @not_present
-	rts
-
-@not_present:
-
-	pla
-	pla
-
-	jsr lowlevel_motor_off             ; if disk not present, disable drive motor
-
-	; XXX set error code, invalidate buffers, etc.
-
-	sec
-	rts
-
-lowlevel_motor_on:
-
-	lda #%00100000                     ; enable drive motor and LED
-	tsb FDC_CONTROL  ; $D080
-	bra lowlevel_wait_clr_BUSY
-
-lowlevel_motor_off:
-
-	lda #%00100000                     ; disable drive motor and LED
-	trb FDC_CONTROL  ; $D080
-
-	; FALLTROUGH
-
-lowlevel_wait_clr_BUSY:
-
-	bit FDC_STATUS_A ; $D082
-	bmi lowlevel_wait_clr_BUSY
-
-	rts
-
-lowlevel_wait_set_RDREQ:
-
-	bit FDC_STATUS_B ; $D083
-	bpl lowlevel_wait_set_RDREQ
-
-	rts

src/dos_m65/lowlevel/lowlevel_helpers_fdc.s

@@ -0,0 +1,74 @@
+
+; Helper routines for low-level disk operations
+
+
+lowlevel_fdc_ensure_presence_refresh:
+
+	jsr lowlevel_fdc_wait_clr_BUSY     ; to be extra sure
+
+	; XXX stepping head is definitely needed, but probably still not enough
+
+	lda #%00011000                     ; step head 1 track in (XXX: check if it is really in)
+	sta FDC_COMMAND  ; $D081
+	jsr lowlevel_fdc_wait_clr_BUSY
+
+	lda #%00010000                     ; step head 1 track out (XXX: check if it is really out)
+	sta FDC_COMMAND  ; $D081
+	jsr lowlevel_fdc_wait_clr_BUSY
+
+	; FALLTROUGH
+
+lowlevel_fdc_ensure_presence:
+
+	lda FDC_STATUS_B ; $D083           ; check if disk is inserted
+	and #$08
+	beq @not_present
+	rts
+
+@not_present:
+
+	pla
+	pla
+
+	jsr lowlevel_fdc_motor_off         ; if disk not present, disable drive motor
+
+	; XXX set error code, invalidate buffers, etc.
+
+	sec
+	rts
+
+lowlevel_fdc_motor_on:
+
+	lda #%00100000                     ; enable drive motor and LED
+	tsb FDC_CONTROL  ; $D080
+
+	; Allow some time for spin-up; according to https://wiki.osdev.org/Floppy_Disk_Controller
+	; 300 ms should be more than enough
+	
+	phx
+	ldx #$0F
+	jsr wait_x_bars
+	plx
+
+	bra lowlevel_fdc_wait_clr_BUSY
+
+lowlevel_fdc_motor_off:
+
+	lda #%00100000                     ; disable drive motor and LED
+	trb FDC_CONTROL  ; $D080
+
+	; FALLTROUGH
+
+lowlevel_fdc_wait_clr_BUSY:
+
+	bit FDC_STATUS_A ; $D082
+	bmi lowlevel_fdc_wait_clr_BUSY
+
+	rts
+
+lowlevel_fdc_wait_set_RDREQ:
+
+	bit FDC_STATUS_B ; $D083
+	bpl lowlevel_fdc_wait_set_RDREQ
+
+	rts

src/dos_m65/lowlevel/lowlevel_readsector.s

@@ -9,7 +9,7 @@ lowlevel_readsector:
 	lda #%00001111                     ; set drive 0 (internal) and side 0
 	trb FDC_CONTROL  ; $D080
 
-	jsr lowlevel_ensure_presence
+	jsr lowlevel_fdc_ensure_presence_refresh
 
 	; Check if buffer contains data from given track
 	; XXX compare device and unit too
@@ -32,8 +32,8 @@ lowlevel_readsector:
 
 lowlevel_readsector_force:
 
-	jsr lowlevel_motor_on              ; enable drive motor and LED
-	jsr lowlevel_ensure_presence
+	jsr lowlevel_fdc_motor_on              ; enable drive motor and LED
+	jsr lowlevel_fdc_ensure_presence
 
 	lda #%10000000                     ; select floppy buffer
 	trb SD_BUFCTL    ; $D689
@@ -74,8 +74,8 @@ lowlevel_readsector_force:
 	lda #$40
 	sta FDC_COMMAND  ; $D081
 
-	jsr lowlevel_wait_set_RDREQ        ; wait till sector is found
-	jsr lowlevel_wait_clr_BUSY         ; wait for BUSY flag to clear
+	jsr lowlevel_fdc_wait_set_RDREQ    ; wait till sector is found
+	jsr lowlevel_fdc_wait_clr_BUSY     ; wait for BUSY flag to clear
 
 	; Wait for DRQ and EQ flags to go high
 
@@ -85,7 +85,7 @@ lowlevel_readsector_force:
 	cmp #%01000000   ; XXX is this correct? .A seems to stay at $40 at this point
 	bne @lp1
 
-	jsr lowlevel_motor_off             ; disable drive motor
+	jsr lowlevel_fdc_motor_off         ; disable drive motor
 
 	; Copy sector to buffer in RAM
 

src/dos_m65/unit_floppy/unit_fd_init.s

@@ -23,6 +23,13 @@ unit_fd_init:
 	sta FD_STATUS_BUF,x
 	bne @1
 
+	; Initialize the controller
+
+	lda #$80       ; default track stepping rate
+	sta FDC_STEP
+	lda #$FF
+	sta FDC_CLOCK
+
 	; End of initialization
 
 	rts