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Added first version of swiftlink driver

git-svn-id: svn://svn.cc65.org/cc65/trunk@2321 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2003-08-15 12:05:56 +00:00
parent f3e0d3fbb1
commit 00b4316ee3

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libsrc/c64/c64-swlink.s Normal file
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;
; Serial driver for the C64 using a Swiftlink or Turbo-232 cartridge.
;
; Ullrich von Bassewitz, 2003-04-18
;
; The driver is based on the cc65 rs232 module, which in turn is based on
; Craig Bruce device driver for the Switftlink/Turbo-232.
;
; SwiftLink/Turbo-232 v0.90 device driver, by Craig Bruce, 14-Apr-1998.
;
; This software is Public Domain. It is in Buddy assembler format.
;
; This device driver uses the SwiftLink RS-232 Serial Cartridge, available from
; Creative Micro Designs, Inc, and also supports the extensions of the Turbo232
; Serial Cartridge. Both devices are based on the 6551 ACIA chip. It also
; supports the "hacked" SwiftLink with a 1.8432 MHz crystal.
;
; The code assumes that the kernal + I/O are in context. On the C128, call
; it from Bank 15. On the C64, don't flip out the Kernal unless a suitable
; NMI catcher is put into the RAM under then Kernal. For the SuperCPU, the
; interrupt handling assumes that the 65816 is in 6502-emulation mode.
;
.include "zeropage.inc"
.include "ser-kernel.inc"
.include "ser-error.inc"
.include "c64.inc"
; ------------------------------------------------------------------------
; Header. Includes jump table
.segment "JUMPTABLE"
; Driver signature
.byte $73, $65, $72 ; "ser"
.byte $00 ; Serial API version number
; Jump table.
.word INSTALL
.word UNINSTALL
.word PARAMS
.word GET
.word PUT
.word PAUSE
.word UNPAUSE
.word STATUS
.word IOCTL
;----------------------------------------------------------------------------
; I/O definitions
ACIA = $DE00
ACIA_DATA = ACIA+0 ; Data register
ACIA_STATUS = ACIA+1 ; Status register
ACIA_CMD = ACIA+2 ; Command register
ACIA_CTRL = ACIA+3 ; Control register
ACIA_CLOCK = ACIA+7 ; Turbo232 external baud-rate generator
;----------------------------------------------------------------------------
;
; Global variables
;
.bss
DropCnt: .res 4 ; Number of bytes lost from rx buffer full
Stopped: .res 1 ; Flow-stopped flag
RtsOff: .res 1 ;
Errors: .res 1 ; Number of bytes received in error, low byte
RecvHead: .res 1 ; Head of receive buffer
RecvTail: .res 1 ; Tail of receive buffer
RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
SendHead: .res 1 ; Head of send buffer
SendTail: .res 1 ; Tail of send buffer
SendFreeCnt: .res 1 ; Number of bytes free in send buffer
BaudCode: .res 1 ; Current baud in effect
; Send and receive buffers: 256 bytes each
RecvBuf: .res 256
SendBuf: .res 256
.data
NmiContinue: .byte $4c ; JMP instruction for NMI save -- continue
NmiSave: .res 2 ; normal NMI handler
.rodata
; Tables used to translate RS232 params into register values
BaudTable: ; bit7 = 1 means setting is invalid
.byte $FF ; SER_BAUD_45_5
.byte $FF ; SER_BAUD_50
.byte $FF ; SER_BAUD_75
.byte $FF ; SER_BAUD_110
.byte $FF ; SER_BAUD_134_5
.byte $FF ; SER_BAUD_150
.byte $05 ; SER_BAUD_300
.byte $06 ; SER_BAUD_600
.byte $07 ; SER_BAUD_1200
.byte $FF ; SER_BAUD_1800
.byte $08 ; SER_BAUD_2400
.byte $FF ; SER_BAUD_3600
.byte $0A ; SER_BAUD_4800
.byte $FF ; SER_BAUD_7200
.byte $0C ; SER_BAUD_9600
.byte $0E ; SER_BAUD_19200
.byte $0F ; SER_BAUD_38400
.byte $FF ; SER_BAUD_57600
.byte $FF ; SER_BAUD_115200
.byte $FF ; SER_BAUD_230400
BitTable:
.byte $60 ; SER_BITS_5
.byte $40 ; SER_BITS_6
.byte $20 ; SER_BITS_7
.byte $00 ; SER_BITS_8
StopTable:
.byte $00 ; SER_STOP_1
.byte $80 ; SER_STOP_2
ParityTable:
.byte $00 ; SER_PAR_NONE
.byte $20 ; SER_PAR_ODD
.byte $60 ; SER_PAR_EVEN
.byte $A0 ; SER_PAR_MARK
.byte $E0 ; SER_PAR_SPACE
HandshakeTable: ; bit7 = 1 means that setting is invalid
.byte $FF ; SER_HS_NONE
.byte $00 ; SER_HS_HW
.byte $FF ; SER_HS_SW
; Delay times: 32 byte-receive times in milliseconds, or 100 max.
; Formula = 320,000 / baud. Invalid values do contain $FF.
PauseTimes:
.byte $FF ; SER_BAUD_45_5
.byte $FF ; SER_BAUD_50
.byte $FF ; SER_BAUD_75
.byte $FF ; SER_BAUD_110
.byte $FF ; SER_BAUD_134_5
.byte $FF ; SER_BAUD_150
.byte 100 ; SER_BAUD_300
.byte 100 ; SER_BAUD_600
.byte 100 ; SER_BAUD_1200
.byte $FF ; SER_BAUD_1800
.byte 100 ; SER_BAUD_2400
.byte $FF ; SER_BAUD_3600
.byte 67 ; SER_BAUD_4800
.byte $FF ; SER_BAUD_7200
.byte 34 ; SER_BAUD_9600
.byte 17 ; SER_BAUD_19200
.byte 9 ; SER_BAUD_38400
.byte $FF ; SER_BAUD_57600
.byte $FF ; SER_BAUD_115200
.byte $FF ; SER_BAUD_230400
.code
;----------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present.
; Must return an SER_ERR_xx code in a/x.
INSTALL:
; Initialize buffers & control
@L4: lda #0
sta RecvHead
sta SendHead
sta RecvTail
sta SendTail
sta Errors
sta Stopped
lda #255
sta RecvFreeCnt
sta SendFreeCnt
; Set up nmi's
lda NMIVec
ldy NMIVec+1
sta NmiSave+0
sty NmiSave+1
lda #<NmiHandler
ldy #>NmiHandler
sta NMIVec
sty NMIVec+1
; Set default to 2400-8N1, enable interrupts
lda ACIA_DATA
lda ACIA_STATUS
lda #$18
sta ACIA_CTRL
lda #$01
sta RtsOff
ora #$08
sta ACIA_CMD
lda #$06
sta BaudCode
; Done, return an error code
lda #SER_ERR_OK
tax
rts
;----------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Must return an SER_ERR_xx code in a/x.
UNINSTALL:
; Stop interrupts, drop DTR
lda RtsOff
and #%11100010
ora #%00000010
sta ACIA_CMD
; Restore NMI vector
lda NmiSave+0
ldy NmiSave+1
sta NMIVec
sty NMIVec+1
; Flag uninitialized
lda #SER_ERR_OK
tax
rts
;----------------------------------------------------------------------------
; PARAMS routine. A pointer to a ser_params structure is passed in ptr1.
; Must return an SER_ERR_xx code in a/x.
PARAMS:
ldy #SER_PARAMS_BAUDRATE
lda (ptr1),y ; Baudrate index
tax
lda BaudTable,x ; Get 6551 value
bmi invalid ; Branch if rate not supported
sta tmp1
iny ; Databits
lda (ptr1),y
tax
lda BitTable,x
ora tmp1
sta tmp1
iny ; Stopbits
lda (ptr1),y
tax
lda StopTable,x
ora tmp1
sta tmp1
iny ; Parity
lda (ptr1),y
tax
lda ParityTable,x
ora tmp1
sta tmp1
iny ; Handshake
lda (ptr1),y
tax
lda HandshakeTable,x
bmi invalid
;----------------------------------------------------------------------------
;
; unsigned char __fastcall__ rs232_params (unsigned char params, unsigned char parity);
; /* Set the port parameters. Use a combination of the #defined values above. */
;
; Set communication parameters.
;
; baud rates stops word | parity
; --------------------- ----- ----- | ---------
; $00=50 $08=9600 $00=1 $00=8 | $00=none
; $01=110 $09=19200 $80=2 $20=7 | $20=odd
; $02=134.5 $0a=38400 $40=6 | $60=even
; $03=300 $0b=57600 $60=5 | $A0=mark
; $04=600 $0c=115200 | $E0=space
; $05=1200 $0d=230400
; $06=2400 $0e=future
; $07=4800 $0f=future
;
_rs232_params:
and #%11100000 ; Save new parity
ora #%00000001
sta tmp2
; Check cpu speed against baud rate
jsr popa
sta tmp1
and #$0f
cmp #$0c
bcc @L3
ldx CpuSpeed ; ###
cpx #1+1
bcc @L2
cmp #$0c
beq @L3
cpx #4
bcs @L3
@L2: lda #RS_ERR_BAUD_TOO_FAST
bne @L9
; Set baud/parameters
@L3: lda tmp1
and #$0f
tax
lda BaudTable,x
cmp #$ff
bne @L5
lda #RS_ERR_BAUD_NOT_AVAIL
bne @L9
@L5: tax
and #$30
beq @L6
bit Turbo232
bmi @L6
lda #RS_ERR_BAUD_NOT_AVAIL
bne @L9
@L6: lda tmp1
and #$0f
sta BaudCode
lda tmp1
and #%11100000
ora #%00010000
sta tmp1
txa
and #$0f
ora tmp1
sta ACIA_CTRL
txa
and #%00110000
beq @L7
lsr
lsr
lsr
lsr
eor #%00000011
sta ACIA_CLOCK
; Set new parity
@L7: lda tmp2
sta RtsOff
ora #%00001000
sta ACIA_CMD
lda #0
@L9: ldx #0
rts
.rodata
BaudTable:
.byte $ff,$ff,$ff,$05,$06,$07,$08,$0a,$0c,$0e,$0f,$10,$20,$30,$ff,$ff
;in: 0 1 2 3 4 5 6 7 8 9 a b c d e f
;baud50 110 134 3 6 12 24 48 96 19 38 57 115 230 exp exp
;out masks: $0F=Baud, val$FF=err
; $30=t232ExtBaud: $00=none, $10=57.6, $20=115.2, $30=230.4
.code
;----------------------------------------------------------------------------
; GET: Will fetch a character from the receive buffer and store it into the
; variable pointer to by ptr1. If no data is available, SER_ERR_NO_DATA is
; return.
;
GET:
; Check for bytes to send
ldx SendFreeCnt
cpx #$ff
beq @L1
lda #$00
jsr TryToSend
; Check for buffer empty
@L1: lda RecvFreeCnt ; (25)
cmp #$ff
bne @L2
lda #SER_ERR_NO_DATA
ldx #0
rts
; Check for flow stopped & enough free: release flow control
@L2: ldx Stopped ; (34)
beq @L3
cmp #63
bcc @L3
lda #$00
sta Stopped
lda RtsOff
ora #%00001000
sta ACIA_CMD
; Get byte from buffer
@L3: ldx RecvHead ; (41)
lda RecvBuf,x
inc RecvHead
inc RecvFreeCnt
ldx #$00 ; (59)
sta (ptr1,x)
txa ; Return code = 0
rts
;----------------------------------------------------------------------------
; PUT: Output character in A.
; Must return an error code in a/x.
;
PUT:
; Try to send
ldx SendFreeCnt
cpx #$ff
beq @L2
pha
lda #$00
jsr TryToSend
pla
; Put byte into send buffer & send
@L2: ldx SendFreeCnt
bne @L3
lda #<SER_ERR_OVERFLOW ; X is already zero
rts
@L3: ldx SendTail
sta SendBuf,x
inc SendTail
dec SendFreeCnt
lda #$ff
jsr TryToSend
lda #<SER_ERR_OK
tax
rts
;----------------------------------------------------------------------------
; PAUSE: Assert flow control and disable interrupts.
; Must return an error code in a/x.
;
PAUSE:
; Assert flow control
lda RtsOff
sta Stopped
sta ACIA_CMD
; Delay for flow stop to be received
ldx BaudCode
ldy PauseTimes,x
jsr DelayMs
; Stop rx interrupts
lda RtsOff
ora #$02
sta ACIA_CMD
lda #<SER_ERR_OK
tax
rts
;----------------------------------------------------------------------------
; UNPAUSE: Re-enable interrupts and release flow control.
; Must return an error code in a/x.
;
UNPAUSE:
; Re-enable rx interrupts & release flow control
@L1: lda #$00
sta Stopped
lda RtsOff
ora #%00001000
sta ACIA_CMD
; Poll for stalled char & exit
jsr PollReceive
lda #<SER_ERR_OK
tax
rts
;----------------------------------------------------------------------------
; STATUS: Return the status in the variable pointed to by ptr1.
; Must return an error code in a/x.
;
STATUS:
; Get status
lda ACIA_STATUS
ldy #0
sta (ptr1),y
jsr PollReceive ; bug-recovery hack
tya ; SER_ERR_OK
tax
rts
;----------------------------------------------------------------------------
;
; NMI handler
; C128 NMI overhead=76 cycles: int=7, maxLatency=6, ROMenter=33, ROMexit=30
; C64 NMI overhead=76 cycles: int=7, maxLatency=6, ROMenter=34, ROMexit=29
;
; timing: normal=76+43+9=128 cycles, assertFlow=76+52+9=137 cycles
;
; C128 @ 115.2k: 177 cycles avail (fast)
; C64 @ 57.6k: 177 cycles avail, worstAvail=177-43? = 134
; SCPU @ 230.4k: 868 cycles avail: for a joke!
;
NmiHandler:
pha
lda ACIA_STATUS ;(4) ;status ;check for byte received
and #$08 ;(2)
beq @L9 ;(2*)
cld
txa
pha
tya
pha
lda ACIA_STATUS ;(4) opt ;status ;check for receive errors
and #$07 ;(2) opt
beq @L1 ;(3*)opt
inc Errors ;(5^)opt
@L1: lda ACIA_DATA ;(4) ;data ;get byte and put into receive buffer
ldy RecvTail ;(4)
ldx RecvFreeCnt ;(4)
beq @L3 ;(2*)
sta RecvBuf,y ;(5)
inc RecvTail ;(6)
dec RecvFreeCnt ;(6)
cpx #33 ;(2) ;check for buffer space low
bcc @L2 ;(2*)
jmp NMIEXIT ;(3)
; Assert flow control
@L2: lda RtsOff ;(3) ;assert flow control if buffer space too low
sta ACIA_CMD ;(4) ;command
sta Stopped ;(3)
jmp NMIEXIT ;(3)
; Drop this char
@L3: inc DropCnt+0 ; not time-critical
bne @L4
inc DropCnt+1
bne @L4
inc DropCnt+2
bne @L4
inc DropCnt+3
@L4: jmp NMIEXIT
@L9: pla
jmp NmiContinue
;----------------------------------------------------------------------------
; Try to send a byte. Internal routine. A = TryHard
.proc TryToSend
sta tmp1 ; Remember tryHard flag
@L0: lda SendFreeCnt
cmp #$ff
beq @L3 ; Bail out
; Check for flow stopped
@L1: lda Stopped
bne @L3 ; Bail out
; Check that swiftlink is ready to send
@L2: lda ACIA_STATUS
and #$10
bne @L4
bit tmp1 ;keep trying if must try hard
bmi @L0
@L3: rts
; Send byte and try again
@L4: ldx SendHead
lda SendBuf,x
sta ACIA_DATA
inc SendHead
inc SendFreeCnt
jmp @L0
.endproc
;----------------------------------------------------------------------------
;
; PollReceive - poll for rx char
; This function is useful in odd cases where the 6551 has a character in
; it but it fails to raise an NMI. It might be edge-triggering conditions?
; Actually, I'm not entirely sure that this condition can still arrise, but
; calling this function does no harm.
;
.proc PollReceive
lda #$08
and ACIA_STATUS
beq @L9
and ACIA_STATUS
beq @L9
lda ACIA_DATA
ldx RecvFreeCnt
beq @L9
ldx RecvTail
sta RecvBuf,x
inc RecvTail
dec RecvFreeCnt
@L9: rts
.endproc
;----------------------------------------------------------------------------
;
; DelayMs : delay for given number of milliseconds
; This implementation isn't very rigerous; it merely delays for the
; approximate number of clock cycles for the processor speed.
; Algorithm:
; repeat for number of milliseconds:
; delay for 1017 clock cycles
;
.proc DelayMs ;( .A=milliseconds )
@L1: ldx #203 ;(2)
@L2: dex ;(2)
bne @L2 ;(3) // 1017 cycles
dey
bne @L1
rts
.endproc
.end