;
.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
.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:
INSTALL:
+; Deactivate DTR and disable 6551 interrupts
+
+ lda #%00001010
+ sta ACIA_CMD
+
; Initialize buffers & control
-@L4: lda #0
- sta RecvHead
- sta SendHead
- sta RecvTail
- sta SendTail
- sta Errors
- sta Stopped
- lda #255
- sta RecvFreeCnt
- sta SendFreeCnt
+@L4: ldx #0
+ stx RecvHead
+ stx SendHead
+ stx RecvTail
+ stx SendTail
+ stx Stopped
+ dex ; X = 255
+ stx RecvFreeCnt
+ stx SendFreeCnt
; Set up nmi's
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:
+
+; First, check if the handshake setting is valid
+
+ ldy #SER_PARAMS_HANDSHAKE ; Handshake
+ lda (ptr1),y
+ cmp #SER_HS_HW ; This is all we support
+ bne InvParam
+
+; 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
- tax
- lda BaudTable,x ; Get 6551 value
- bmi invalid ; Branch if rate not supported
+ tay
+ lda BaudTable,y ; Get 6551 value
+ bmi InvBaud ; Branch if rate not supported
sta tmp1
+ sty BaudCode ; Remember baud rate index
- iny ; Databits
+ ldy #SER_PARAMS_DATABITS ; Databits
lda (ptr1),y
- tax
- lda BitTable,x
+ tay
+ lda BitTable,y
ora tmp1
sta tmp1
- iny ; Stopbits
+ ldy #SER_PARAMS_STOPBITS ; Stopbits
lda (ptr1),y
- tax
- lda StopTable,x
+ tay
+ lda StopTable,y
ora tmp1
- sta tmp1
+ ora #%00010000 ; Receiver clock source = baudrate
+ sta ACIA_CTRL
- iny ; Parity
- lda (ptr1),y
- tax
- lda ParityTable,x
- ora tmp1
- sta tmp1
+; Set the value for the command register. We remember the base value in
+; RtsOff, since we will have to manipulate ACIT_CMD often.
- iny ; Handshake
+ 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 #%00010000 ; Enable receive interrupts
+ sta ACIA_CMD
+; Done
+ lda #<SER_ERR_OK
+ tax ; A is zero
+ rts
-;----------------------------------------------------------------------------
-;
-; 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
+; Invalid parameter
-@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
+InvParam:
+ lda #<SER_ERR_INIT_FAILED
+ ldx #>SER_ERR_INIT_FAILED
+ rts
-.rodata
+; Baud rate not available
-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, $30=230.4
-.code
+InvBaud:
+ lda #<SER_ERR_BAUD_UNAVAIL
+ ldx #>SER_ERR_BAUD_UNAVAIL
+ rts
;----------------------------------------------------------------------------
; GET: Will fetch a character from the receive buffer and store it into the
; Check for bytes to send
ldx SendFreeCnt
- cpx #$ff
+ 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
; Stop rx interrupts
lda RtsOff
- ora #$02
+ ora #%00000010 ; Disable interrupts
sta ACIA_CMD
lda #<SER_ERR_OK
tax
;
STATUS:
-
-; Get status
-
lda ACIA_STATUS
ldy #0
sta (ptr1),y
- jsr PollReceive ; bug-recovery hack
+ jsr PollReceive ; bug-recovery hack
tya ; SER_ERR_OK
tax
rts
+;----------------------------------------------------------------------------
+; 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.
+;
+
+IOCTL:
+ lda #<SER_ERR_INV_IOCTL ; We don't support ioclts for now
+ ldx #>SER_ERR_INV_IOCTL
+ rts
+
;----------------------------------------------------------------------------
;
; NMI handler
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
projects / cc65 / commitdiff