; Driver signature
.byte $73, $65, $72 ; "ser"
- .byte $00 ; Serial API version number
+ .byte SER_API_VERSION ; Serial API version number
; Jump table.
.word INSTALL
.word UNINSTALL
- .word PARAMS
+ .word OPEN
+ .word CLOSE
.word GET
.word PUT
- .word PAUSE
- .word UNPAUSE
.word STATUS
.word IOCTL
+ .word IRQ
;----------------------------------------------------------------------------
; I/O definitions
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
;
+; We reuse the RS232 zero page variables for the driver, since the ROM
+; routines cannot be used together with this driver.
+RecvHead = $B5 ; Head of receive buffer
+RecvTail = $BD ; Tail of receive buffer
+RecvFreeCnt = $F7 ; Number of bytes in receive buffer
+SendHead = $F8 ; Head of send buffer
+SendTail = $F9 ; Tail of send buffer
+SendFreeCnt = $FA ; Number of bytes free in send buffer
+
.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
.byte $FF ; SER_BAUD_75
.byte $FF ; SER_BAUD_110
.byte $FF ; SER_BAUD_134_5
- .byte $FF ; SER_BAUD_150
+ .byte $02 ; 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 $09 ; SER_BAUD_3600
.byte $0A ; SER_BAUD_4800
- .byte $FF ; SER_BAUD_7200
+ .byte $0B ; SER_BAUD_7200
.byte $0C ; SER_BAUD_9600
.byte $0E ; SER_BAUD_19200
.byte $0F ; SER_BAUD_38400
.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:
-; Initialize buffers & control
+; Deactivate DTR and disable 6551 interrupts
-@L4: lda #0
- sta RecvHead
- sta SendHead
- sta RecvTail
- sta SendTail
- sta Errors
- sta Stopped
- lda #255
- sta RecvFreeCnt
- sta SendFreeCnt
+ lda #%00001010
+ sta ACIA_CMD
-; Set up nmi's
+; Set up the nmi vector
lda NMIVec
ldy NMIVec+1
sty NmiSave+1
lda #<NmiHandler
ldy #>NmiHandler
- sta NMIVec
+SetNMI: 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
+ lda #<SER_ERR_OK
+ tax ; A is zero
rts
;----------------------------------------------------------------------------
; Stop interrupts, drop DTR
- lda RtsOff
- and #%11100010
- ora #%00000010
- sta ACIA_CMD
+ lda #%00001010
+ sta ACIA_CMD
-; Restore NMI vector
+; Restore NMI vector and return OK
lda NmiSave+0
ldy NmiSave+1
- sta NMIVec
- sty NMIVec+1
-
-; Flag uninitialized
-
- lda #SER_ERR_OK
- tax
- rts
+ jmp SetNMI
;----------------------------------------------------------------------------
; 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
+OPEN:
+
+; Check if the handshake setting is valid
- iny ; Databits
+ ldy #SER_PARAMS::HANDSHAKE ; Handshake
lda (ptr1),y
- tax
- lda BitTable,x
- ora tmp1
+ cmp #SER_HS_HW ; This is all we support
+ bne InvParam
+
+; Initialize buffers
+
+ jsr InitBuffers
+
+; Set the value for the control register, which contains stop bits, word
+; length and the baud rate.
+
+ ldy #SER_PARAMS::BAUDRATE
+ lda (ptr1),y ; Baudrate index
+ tay
+ lda BaudTable,y ; Get 6551 value
+ bmi InvBaud ; Branch if rate not supported
sta tmp1
- iny ; Stopbits
+ ldy #SER_PARAMS::DATABITS ; Databits
lda (ptr1),y
- tax
- lda StopTable,x
+ tay
+ lda BitTable,y
ora tmp1
sta tmp1
- iny ; Parity
+ ldy #SER_PARAMS::STOPBITS ; Stopbits
lda (ptr1),y
- tax
- lda ParityTable,x
+ tay
+ lda StopTable,y
ora tmp1
- sta tmp1
+ ora #%00010000 ; Receiver clock source = baudrate
+ sta ACIA_CTRL
- iny ; Handshake
+; Set the value for the command register. We remember the base value in
+; RtsOff, since we will have to manipulate ACIA_CMD often.
+
+ ldy #SER_PARAMS::PARITY ; Parity
lda (ptr1),y
- tax
- lda HandshakeTable,x
- bmi invalid
+ tay
+ lda ParityTable,y
+ ora #%00000001 ; DTR active
+ sta RtsOff
+ ora #%00001000 ; Enable receive interrupts
+ sta ACIA_CMD
+; Done
+ lda #<SER_ERR_OK
+ tax ; A is zero
+ rts
+
+; Invalid parameter
+InvParam:
+ lda #<SER_ERR_INIT_FAILED
+ ldx #>SER_ERR_INIT_FAILED
+ rts
+; Baud rate not available
+InvBaud:
+ lda #<SER_ERR_BAUD_UNAVAIL
+ ldx #>SER_ERR_BAUD_UNAVAIL
+ rts
;----------------------------------------------------------------------------
+; CLOSE: Close the port, disable interrupts and flush the buffer. Called
+; without parameters. Must return an error code in a/x.
;
-; 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
+CLOSE:
- jsr popa
- sta tmp1
- and #$0f
- cmp #$0c
- bcc @L3
+; Stop interrupts, drop DTR
- ldx CpuSpeed ; ###
- cpx #1+1
- bcc @L2
- cmp #$0c
- beq @L3
- cpx #4
- bcs @L3
-@L2: lda #RS_ERR_BAUD_TOO_FAST
- bne @L9
+ lda #%00001010
+ sta ACIA_CMD
-; Set baud/parameters
+; Initalize buffers. Returns zero in a
-@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
+ jsr InitBuffers
-.rodata
+; Return OK
-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, $30=230.4
-.code
+ lda #<SER_ERR_OK
+ tax ; A is zero
+ rts
;----------------------------------------------------------------------------
; GET: Will fetch a character from the receive buffer and store it into the
; return.
;
-GET:
-
-; Check for bytes to send
-
- ldx SendFreeCnt
- cpx #$ff
+GET: ldx SendFreeCnt ; Send data if necessary
+ inx ; X == $FF?
beq @L1
lda #$00
jsr TryToSend
@L1: lda RecvFreeCnt ; (25)
cmp #$ff
bne @L2
- lda #SER_ERR_NO_DATA
- ldx #0
+ lda #<SER_ERR_NO_DATA
+ ldx #>SER_ERR_NO_DATA
rts
; Check for flow stopped & enough free: release flow control
rts
;----------------------------------------------------------------------------
-; PUT: Output character in A.
+; PUT: Output character in A.
; Must return an error code in a/x.
;
; Try to send
ldx SendFreeCnt
- cpx #$ff
+ inx ; X = $ff?
beq @L2
pha
lda #$00
rts
;----------------------------------------------------------------------------
-; PAUSE: Assert flow control and disable interrupts.
+; STATUS: Return the status in the variable pointed to by ptr1.
; 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
-
+STATUS: lda ACIA_STATUS
+ ldx #0
+ sta (ptr1,x)
+ txa ; SER_ERR_OK
+ rts
;----------------------------------------------------------------------------
-; UNPAUSE: Re-enable interrupts and release flow control.
+; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
+; specific data in ptr1, and the ioctl code in A.
; 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
+IOCTL: lda #<SER_ERR_INV_IOCTL ; We don't support ioclts for now
+ ldx #>SER_ERR_INV_IOCTL
+ rts
;----------------------------------------------------------------------------
-; STATUS: Return the status in the variable pointed to by ptr1.
-; Must return an error code in a/x.
+; IRQ: Not used on the C64
;
-STATUS:
-
-; Get status
-
- lda ACIA_STATUS
- ldy #0
- sta (ptr1),y
- jsr PollReceive ; bug-recovery hack
- tya ; SER_ERR_OK
- tax
- rts
+IRQ = $0000
;----------------------------------------------------------------------------
;
NmiHandler:
pha
- lda ACIA_STATUS ;(4) ;status ;check for byte received
- and #$08 ;(2)
- beq @L9 ;(2*)
+ 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)
+@L1: lda ACIA_DATA ;(4) data ;get byte and put into receive buffer
+ ldy RecvTail ;(4)
+ ldx RecvFreeCnt ;(4)
+ beq @L3 ;(2*) Jump if no space in receive buffer
+ 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
+@L2: lda RtsOff ;(3) assert flow control if buffer space too low
+ sta ACIA_CMD ;(4) command
+ sta Stopped ;(3)
+@L3: jmp NMIEXIT ;(3)
@L9: pla
jmp NmiContinue
.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
-
-
+; Initialize buffers
+
+InitBuffers:
+ ldx #0
+ stx Stopped
+ stx RecvHead
+ stx RecvTail
+ stx SendHead
+ stx SendTail
+ dex ; X = 255
+ stx RecvFreeCnt
+ stx SendFreeCnt
+ rts
projects / cc65 / blobdiff