AppleIISd/src/AppleIISd.s

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;*******************************
;
; Apple][Sd Firmware
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; Version 1.0
;
; (c) Florian Reitz, 2017
;
; X register usually contains SLOT16
; Y register is used for counting or SLOT
;
;*******************************
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.define DEBUG 0
; Memory defines
SLOT16 := $2B ; $s0 -> slot * 16
SLOT := $3D ; $0s
CMDLO := $40
CMDHI := $41
DCMD := $42 ; Command code
BUFFER := $44 ; Buffer address
BLOCK := $46 ; Block number
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R30 := $0478
R31 := $04F8
R32 := $0578
R33 := $05F8
CURSLOT := $07F8 ; $Cs
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OAPPLE := $C061 ; open apple key
DATA := $C080
CTRL := DATA+1
DIV := DATA+2
SS := DATA+3
; Constants
DUMMY = $FF
FRX = $10 ; CTRL register
ECE = $04
SS0 = $01 ; SS register
SDHC = $10
WP = $20
CD = $40
INITED = $80
; signature bytes
.segment "SLOTROM"
LDX #$20
LDX #$00
LDX #$03
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LDX #$3C
; find slot nr
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.if DEBUG
LDA #$04
STA SLOT
LDA #$C4
STA CURSLOT
LDA #$40
.else
PHP
SEI
LDA #$60 ; opcode for RTS
STA SLOT
JSR SLOT
TSX
LDA $0100,X
STA CURSLOT ; $Cs
AND #$0F
PLP
STA SLOT ; $0s
ASL A
ASL A
ASL A
ASL A
.endif
STA SLOT16 ; $s0
TAX ; X holds now SLOT16
BIT $CFFF
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LDY #0 ; display copyright message
@DRAW: LDA TEXT,Y
BEQ @OAPPLE ; check for NULL
ORA #$80
STA $0750,Y ; put second to last line
INY
BPL @DRAW
@OAPPLE: BIT OAPPLE ; check for OA key
BMI @NEXTSLOT ; and skip boot if pressed
JSR CARDDET
BCC @INIT
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@NEXTSLOT: LDA CURSLOT ; skip boot when no card
DEC A
STA CMDHI
STZ CMDLO
JMP (CMDLO)
@INIT: JSR INIT
;*******************************
;
; Install SD card driver
;
;*******************************
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.if DEBUG
; see if slot has a driver already
LDX $BF31 ; get devcnt
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@INSTALL: LDA $BF32,X ; get a devnum
AND #$70 ; isolate slot
CMP SLOT16 ; slot?
BEQ @INSOUT ; yes, skip it
DEX
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BPL @INSTALL ; keep up the search
; restore the devnum to the list
LDX $BF31 ; get devcnt again
CPX #$0D ; device table full?
BNE @INST2
JSR $FF3A ; bell
JMP @INSOUT ; do something!
@INST2: LDA $BF32-1,X ; move all entries down
STA $BF32,X ; to make room at front
DEX ; for a new entry
BNE @INST2
LDA #$04 ; ProFile type device
ORA SLOT16
STA $BF32 ; slot, drive 1 at top of list
INC $BF31 ; update devcnt
; now insert the device driver vector
LDA SLOT
ASL
TAX
LDA #<DRIVER
STA $BF10,X ; write to driver table
LDA #>DRIVER
STA $BF11,X
@INSOUT: RTS
;*******************************
;
; Boot from SD card
;
;*******************************
.else
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@BOOT: LDA #$01
STA DCMD ; load command
LDX SLOT16
STX $43 ; slot number
LDA #$08
STA BUFFER+1 ; buffer hi
STZ BUFFER ; buffer lo
STZ BLOCK+1 ; block hi
STZ BLOCK ; block lo
BIT $CFFF
JSR READ ; call driver
LDA #$01
STA DCMD ; load command
LDX SLOT16
STX $43 ; slot number
LDA #$0A
STA BUFFER+1 ; buffer hi
STZ BUFFER ; buffer lo
STZ BLOCK+1 ; block hi
LDA #$01
STA BLOCK ; block lo
BIT $CFFF
JSR READ ; call driver
LDX SLOT16
JMP $801 ; goto bootloader
.endif
;*******************************
;
; Jump table
;
;*******************************
DRIVER: CLD
@SAVEZP: PHA ; make room for retval
LDA SLOT16 ; save all ZP locations
PHA
LDA SLOT
PHA
LDA CMDLO
PHA
LDA CMDHI
PHA
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.if DEBUG
LDA #$04
STA SLOT
LDA #$C4
STA CURSLOT
LDA #$40
.else
PHP
SEI
LDA #$60 ; opcode for RTS
STA SLOT
JSR SLOT
TSX
LDA $0100,X
STA CURSLOT ; $Cs
AND #$0F
PLP
STA SLOT ; $0s
ASL A
ASL A
ASL A
ASL A
.endif
STA SLOT16 ; $s0
TAX ; X holds now SLOT16
BIT $CFFF
JSR CARDDET
BCC @INITED
LDA #$2F ; no card inserted
BRA @RESTZP
@INITED: LDA #INITED ; check for init
BIT SS,X
BEQ @INIT
@CMD: LDA DCMD ; get command
BEQ @STATUS ; branch if cmd is 0
CMP #1
BEQ @READ
CMP #2
BEQ @WRITE
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.if DEBUG
CMP #$FF
BEQ @TEST
.endif
LDA #1 ; unknown command
SEC
BRA @RESTZP
@STATUS: JSR STATUS
BRA @RESTZP
@READ: JSR READ
BRA @RESTZP
@WRITE: JSR WRITE
BRA @RESTZP
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.if DEBUG
@TEST: JSR TEST ; do device test
BRA @RESTZP
.endif
@INIT: JSR INIT
BCC @CMD ; init ok
@RESTZP: TSX
STA $105,X ; save retval on stack
PLA ; restore all ZP locations
STA CMDHI
PLA
STA CMDLO
PLA
STA SLOT
PLA
STA SLOT16
PLA ; get retval
RTS
; Signature bytes
.segment "SLOTID"
.dbyt $FFFF ; 65535 blocks
.byt $97 ; Status bits
.byt <DRIVER ; LSB of driver
;*******************************
;
; Initialize SD card
;
; C Clear - No error
; Set - Error
; A $00 - No error
; $27 - I/O error - Init failed
; $2F - No card inserted
;
;*******************************
.segment "EXTROM"
INIT: LDA #$03 ; set SPI mode 3
STA CTRL,X
LDA SS,X
ORA #SS0 ; set CS high
STA SS,X
LDA #7
STA DIV,X
LDY #10
LDA #DUMMY
@LOOP: STA DATA,X
@WAIT: BIT CTRL,X
BPL @WAIT
DEY
BNE @LOOP ; do 10 times
LDA SS,X
AND #<~SS0 ; set CS low
STA SS,X
LDA #<CMD0 ; send CMD0
STA CMDLO
LDA #>CMD0
STA CMDHI
JSR SDCMD
JSR GETR1 ; get response
CMP #$01
BNE @ERROR1 ; error!
LDA #<CMD8 ; send CMD8
STA CMDLO
LDA #>CMD8
STA CMDHI
JSR SDCMD
JSR GETR3
CMP #$01
BNE @SDV1 ; may be SD Ver. 1
; check for $01aa match!
@SDV2: LDA #<CMD55
STA CMDLO
LDA #>CMD55
STA CMDHI
JSR SDCMD
JSR GETR1
LDA #<ACMD4140
STA CMDLO
LDA #>ACMD4140
STA CMDHI
JSR SDCMD
JSR GETR1
CMP #$01
BEQ @SDV2 ; wait for ready
CMP #0
BNE @ERROR1 ; error!
; send CMD58
; SD Ver. 2 initialized!
LDA SS,X
ORA #SDHC
STA SS,X
JMP @BLOCKSZ
@ERROR1: JMP @IOERROR ; needed for far jump
@SDV1: LDA #<CMD55
STA CMDLO
LDA #>CMD55
STA CMDHI
JSR SDCMD ; ignore response
LDA #<ACMD410
STA CMDLO
LDA #>ACMD410
STA CMDHI
JSR SDCMD
JSR GETR1
CMP #$01
BEQ @SDV1 ; wait for ready
CMP #0
BNE @MMC ; may be MMC card
; SD Ver. 1 initialized!
JMP @BLOCKSZ
@MMC: LDA #<CMD1
STA CMDLO
LDA #>CMD1
STA CMDHI
@LOOP1: JSR SDCMD
JSR GETR1
CMP #$01
BEQ @LOOP1 ; wait for ready
CMP #0
BNE @IOERROR ; error!
; MMC Ver. 3 initialized!
@BLOCKSZ: LDA #<CMD16
STA CMDLO
LDA #>CMD16
STA CMDHI
JSR SDCMD
JSR GETR1
CMP #0
BNE @IOERROR ; error!
@END: LDA SS,X
ORA #INITED ; initialized
STA SS,X
LDA CTRL,X
ORA #ECE ; enable 7MHz
STA CTRL,X
CLC ; all ok
LDY #0
BCC @END1
@IOERROR: SEC
LDY #$27 ; init error
@END1: LDA SS,X ; set CS high
ORA #SS0
STA SS,X
LDA #0 ; set div to 2
STA DIV,X
TYA ; retval in A
RTS
;*******************************
;
; Send SD command
; Call with command in CMDHI and CMDLO
;
;*******************************
SDCMD: PHY
LDY #0
@LOOP: LDA (CMDLO),Y
STA DATA,X
@WAIT: BIT CTRL,X ; TC is in N
BPL @WAIT
INY
CPY #6
BCC @LOOP
PLY
RTS
;*******************************
;
; Get R1
; R1 is in A
;
;*******************************
GETR1: LDA #DUMMY
STA DATA,X
@WAIT: BIT CTRL,X
BPL @WAIT
LDA DATA,X ; get response
BIT #$80
BNE GETR1 ; wait for MSB=0
PHA
LDA #DUMMY
STA DATA,X ; send another dummy
PLA ; restore R1
RTS
;*******************************
;
; Get R3
; R1 is in A
; R3 is in scratchpad ram
;
;*******************************
GETR3: JSR GETR1 ; get R1 first
PHA ; save R1
PHY ; save Y
LDY #04 ; load counter
@LOOP: LDA #DUMMY ; send dummy
STA DATA,X
@WAIT: BIT CTRL,X
BPL @WAIT
LDA DATA,X
PHA
DEY
BNE @LOOP ; do 4 times
LDY SLOT
PLA
STA R33,Y ; save R3
PLA
STA R32,Y
PLA
STA R31,Y
PLA
STA R30,Y
PLY ; restore Y
LDA #DUMMY
STA DATA,X ; send another dummy
PLA ; restore R1
RTS
;*******************************
;
; Calculate block address
; Unit number is in $43 DSSS0000
; Block no is in $46-47
; Address is in R30-R33
;
;*******************************
GETBLOCK: PHX ; save X
PHY ; save Y
TXA
TAY ; SLOT16 is now in Y
LDX SLOT
LDA BLOCK ; store block num
STA R33,X ; in R30-R33
LDA BLOCK+1
STA R32,X
LDA #0
STA R31,X
STA R30,X
LDA #$80 ; drive number
AND $43
BEQ @SDHC ; D1
LDA #1 ; D2
STA R31,X
@SDHC: LDA #SDHC
AND SS,Y ; if card is SDHC,
BNE @END ; use block addressing
LDY #9 ; ASL can't be used with Y
@LOOP: ASL R33,X ; mul block num
ROL R32,X ; by 512 to get
ROL R31,X ; real address
ROL R30,X
DEY
BNE @LOOP
@END: PLY ; restore Y
PLX ; restore X
RTS
;*******************************
;
; Send SD command
; Cmd is in A
;
;*******************************
COMMAND: PHY ; save Y
LDY SLOT
STA DATA,X ; send command
LDA R30,Y ; get arg from R30 on
STA DATA,X
LDA R31,Y
STA DATA,X
LDA R32,Y
STA DATA,X
LDA R33,Y
STA DATA,X
LDA #DUMMY
STA DATA,X ; dummy crc
JSR GETR1
PLY ; restore Y
RTS
;*******************************
;
; Check for card detect
;
; C Clear - card in slot
; Set - no card in slot
;
;*******************************
CARDDET: PHA
LDA #CD ; 0: card in
BIT SS,X ; 1: card out
CLC
BEQ @DONE ; card is in
SEC ; card is out
@DONE: PLA
RTS
;*******************************
;
; Check for write protect
;
; C Clear - card not protected
; Set - card write protected
;
;*******************************
WRPROT: PHA
LDA #WP ; 0: write enabled
BIT SS,X ; 1: write disabled
CLC
BEQ @DONE
SEC
@DONE: PLA
RTS
;*******************************
;
; Status request
; $43 Unit number DSSS000
; $44-45 Unused
; $46-47 Unused
;
; C Clear - No error
; Set - Error
; A $00 - No error
; $2B - Card write protected
; $2F - No card inserted
; X - Blocks avail (low byte)
; Y - Blocks avail (high byte)
;
;*******************************
STATUS: LDA #0 ; no error
JSR WRPROT
BCC @DONE
LDA #$2B ; card write protected
@DONE: LDX #$FF ; 32 MB partition
LDY #$FF
RTS
;*******************************
;
; Read 512 byte block
; $43 Unit number DSSS0000
; $44-45 Address (LO/HI) of buffer
; $46-47 Block number (LO/HI)
;
; C Clear - No error
; Set - Error
; A $00 - No error
; $27 - Bad block number
;
;*******************************
READ: JSR GETBLOCK ; calc block address
LDA SS,X ; enable /CS
AND #<~SS0
STA SS,X
LDA #$51 ; send CMD17
JSR COMMAND ; send command
CMP #0
BNE @ERROR ; check for error
@GETTOK: LDA #DUMMY ; get data token
STA DATA,X
LDA DATA,X ; get response
CMP #$FE
BNE @GETTOK ; wait for $FE
LDA CTRL,X ; enable FRX
ORA #FRX
STA CTRL,X
LDA #DUMMY
STA DATA,X
LDY #0
@LOOP1: LDA DATA,X ; read data from card
STA (BUFFER),Y
INY
BNE @LOOP1
INC BUFFER+1 ; inc msb on page boundary
@LOOP2: LDA DATA,X
STA (BUFFER),Y
INY
BNE @LOOP2
DEC BUFFER+1
@CRC: LDA DATA,X ; read two bytes crc
LDA DATA,X ; and ignore
LDA DATA,X ; read a dummy byte
LDA CTRL,X ; disable FRX
AND #<~FRX
STA CTRL,X
CLC ; no error
LDA #0
@DONE: PHP
PHA
LDA SS,X
ORA #SS0
STA SS,X ; disable /CS
PLA
PLP
RTS
@ERROR: SEC ; an error occured
LDA #$27
BRA @DONE
;*******************************
;
; Write 512 byte block
; $43 Unit number DSSS0000
; $44-45 Address (LO/HI) of buffer
; $46-47 Block number (LO/HI)
;
; C Clear - No error
; Set - Error
; A $00 - No error
; $27 - I/O error or bad block number
; $2B - Card write protected
;
;*******************************
WRITE: JSR WRPROT
BCS @WPERROR ; card write protected
JSR GETBLOCK ; calc block address
LDA SS,X ; enable /CS
AND #<~SS0
STA SS,X
LDA #$58 ; send CMD24
JSR COMMAND ; send command
CMP #0
BNE @IOERROR ; check for error
LDA #DUMMY
STA DATA,X ; send dummy
LDA #$FE
STA DATA,X ; send data token
LDY #0
@LOOP1: LDA (BUFFER),Y
STA DATA,X
INY
BNE @LOOP1
INC BUFFER+1
@LOOP2: LDA (BUFFER),Y
STA DATA,X
INY
BNE @LOOP2
DEC BUFFER+1
@CRC: LDA #DUMMY
STA DATA,X ; send 2 dummy crc bytes
STA DATA,X
STA DATA,X ; get data response
LDA DATA,X
AND #$1F
CMP #$05
BNE @IOERROR ; check for write error
CLC ; no error
LDA #0
@DONE: PHP
PHA
@WAIT: LDA #DUMMY
STA DATA,X ; wait for write cycle
LDA DATA,X ; to complete
BEQ @WAIT
LDA SS,X ; disable /CS
ORA #SS0
STA SS,X
PLA
PLP
RTS
@IOERROR: SEC ; an error occured
LDA #$27
BRA @DONE
@WPERROR: SEC
LDA #$2B
BRA @DONE
;*******************************
;
; Test routine
;
;*******************************
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.if DEBUG
TEST: LDA SLOT16
PHA
LDA SLOT
PHA
; get buffer
LDA #2 ; get 512 byte buffer
JSR $BEF5 ; call GETBUFR
BCS @ERROR
STA BUFFER+1
STZ BUFFER
PLA
STA SLOT
PLA
STA SLOT16
; fill buffer
LDY #0
@LOOP: TYA
STA (BUFFER),Y
INY
BNE @LOOP
INC BUFFER+1
@LOOP1: TYA
STA (BUFFER),Y
INY
BNE @LOOP1
DEC BUFFER+1
STZ BLOCK ; block number
STZ BLOCK+1
LDX SLOT16
; write to card
JSR WRITE
BCS @ERROR
; read from card
JSR READ
BCS @ERROR
; check for errors
LDY #0
@LOOP2: TYA
CMP (BUFFER),Y
BNE @ERRCMP ; error in buffer
INY
BNE @LOOP2
INC BUFFER+1
@LOOP3: TYA
CMP (BUFFER),Y
BNE @ERRCMP
INY
BNE @LOOP3
DEC BUFFER+1
; free buffer
JSR $BEF8 ; call FREEBUFR
CLC
LDA #0
RTS
@ERROR: BRK
@ERRCMP: BRK
.endif
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TEXT: .asciiz " Apple][Sd v1.0 (c)2017 Florian Reitz"
CMD0: .byt $40, $00, $00
.byt $00, $00, $95
CMD1: .byt $41, $00, $00
.byt $00, $00, $F9
CMD8: .byt $48, $00, $00
.byt $01, $AA, $87
CMD16: .byt $50, $00, $00
.byt $02, $00, $FF
CMD55: .byt $77, $00, $00
.byt $00, $00, $65
ACMD4140: .byt $69, $40, $00
.byt $00, $00, $77
ACMD410: .byt $69, $00, $00
.byt $00, $00, $FF