+++ /dev/null
-;
-; 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.
-;
-;--------------------------------------------------------------------------
-;
-; Adapted for the use with the cc65 runtime library by
-; Ullrich von Bassewitz (uz@musoftware.de) 02-May-1999.
-;
-; All external functions are C callable, the return value is an error code.
-;
-
-
- .importzp ptr1, ptr2, tmp1, tmp2
- .importzp acia, RecvBuf, SendBuf
- .import popa, popax
- .import sys_bank, restore_bank
- .export _rs232_init, _rs232_params, _rs232_done, _rs232_get
- .export _rs232_put, _rs232_pause, _rs232_unpause, _rs232_status
- .export k_rs232
-
- .include "cbm610.inc"
-
-
-;----------------------------------------------------------------------------
-;
-; Global variables
-;
-
-.bss
-DropCnt: .res 4 ; Number of bytes lost from rx buffer full
-Initialized: .res 1 ; Flag indicating driver is initialized
-Stopped: .res 1 ; Flow-stopped flag
-RtsOff: .res 1 ;
-Errors: .res 1 ; Number of bytes received in error, low byte
-BaudCode: .res 1 ; Current baud in effect
-
-; Segment, the RS232 buffers are in
-BufferSeg = 2
-
-; UART register offsets
-RegData = 0 ; Data register
-RegStatus = 1 ; Status register
-RegCommand = 2 ; Command register
-RegControl = 3 ; Control register
-
-; Error codes. Beware: The codes must match the codes in the C header file
-ErrNotInitialized = $01
-ErrBaudTooFast = $02
-ErrBaudNotAvail = $03
-ErrNoData = $04
-ErrOverflow = $05
-
-
-.code
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_init (char hacked);
-; /* Initialize the serial port, install the interrupt handler. The parameter
-; * must be true (non zero) for a hacked swiftlink and false (zero) otherwise.
-; */
-;
-
-_rs232_init:
- bit Initialized ;** shut down if started
- bpl @L1
- pha
- jsr _rs232_done
- pla
-
-; Initialize buffers & control
-
-@L1: lda #0
- sta RecvHead
- sta SendHead
- sta RecvTail
- sta SendTail
- sta Errors
- sta Stopped
- lda #255
- sta RecvFreeCnt
- sta SendFreeCnt
-
-; Set default to 2400-8N1, enable interrupts
-
- jsr sys_bank ; Switch indirect to system bank
-
- ldy #RegData
- lda (acia),y
- ldy #RegStatus
- lda (acia),y
- lda #$18
- ldy #RegControl
- sta (acia),y
-
- lda #$01
- sta RtsOff
- ora #$08
- ldy #RegCommand
- sta (acia),y
- lda #$06
- sta BaudCode
-
- jsr restore_bank
-
- lda #$ff
- sta Initialized
- lda #$00
- tax
- 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:
- jsr CheckInitialized ;** check initialized
- bcc @L1
- rts
-
-; Save new parity
-
-@L1: and #%11100000
- ora #%00000001
- sta tmp2
-
-; Set baud/parameters
-
- jsr popa
- sta tmp1
- and #$0f
- tax
- lda Bauds,x
- cmp #$ff
- bne @L5
- lda #ErrBaudNotAvail
- bne @L9
-
-@L5: jsr sys_bank ; Indirect segment to system bank
- tax
- lda tmp1
- and #$0f
- sta BaudCode
- lda tmp1
- and #%11100000
- ora #%00010000
- sta tmp1
- txa
- and #$0f
- ora tmp1
- ldy #RegControl
- sta (acia),y
-
-; Set new parity
-
-@L7: lda tmp2
- sta RtsOff
- ora #%00001000
- ldy #RegCommand
- sta (acia),y
- jsr restore_bank ; Restore indirect bank
- lda #0
-@L9: ldx #0
- rts
-
-.rodata
-Bauds:
- .byte $01,$03,$04,$06,$07,$08,$0a,$0c,$0e,$0f,$ff,$ff,$ff,$ff,$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
-.code
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_done (void);
-; /* Close the port, deinstall the interrupt hander. You MUST call this function
-; * before terminating the program, otherwise the machine may crash later. If
-; * in doubt, install an exit handler using atexit(). The function will do
-; * nothing, if it was already called.
-; */
-;
-
-
-_rs232_done:
- bit Initialized ;** check initialized
- bpl @L9
-
-; Stop interrupts, drop DTR
-
- lda RtsOff
- and #%11100010
- ora #%00000010
- ldx IndReg
- ldy #$0F
- sty IndReg ; Set indirect to system bank
- ldy #RegCommand
- sta (acia),y
- stx IndReg ; Restore old indirect bank
-
-; Flag uninitialized
-
-@L9: lda #$00
- sta Initialized
- tax
- rts
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_get (char* B);
-; /* Get a character from the serial port. If no characters are available, the
-; * function will return RS_ERR_NO_DATA, so this is not a fatal error.
-; */
-;
-
-_rs232_get:
- jsr CheckInitialized ; Check if initialized
- bcc @L1
- rts
-
-; Check for bytes to send
-
-@L1: sta ptr1
- stx ptr1+1 ; Store pointer to received char
- ldx SendFreeCnt
- cpx #$ff
- beq @L2
- lda #$00
- jsr TryToSend
-
-; Check for buffer empty
-
-@L2: lda RecvFreeCnt
- cmp #$ff
- bne @L3
- lda #ErrNoData
- ldx #0
- rts
-
-; Check for flow stopped & enough free: release flow control
-
-@L3: ldx Stopped
- beq @L4
- cmp #63
- bcc @L4
- lda #$00
- sta Stopped
- lda RtsOff
- ora #%00001000
- ldx IndReg
- ldy #$0F ; Set indirect to system bank
- sty IndReg
- ldy #RegCommand
- sta (acia),y
- stx IndReg
-
-; Get byte from buffer
-
-@L4: ldx IndReg
- lda #BufferSeg ; Set indirect to buffer bank
- sta IndReg
- ldy RecvHead
- lda (RecvBuf),y
- stx IndReg ; Restore indirect bank
- inc RecvHead
- inc RecvFreeCnt
- ldx #$00
- sta (ptr1,x)
- txa ; Return code = 0
- rts
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_put (char B);
-; /* Send a character via the serial port. There is a transmit buffer, but
-; * transmitting is not done via interrupt. The function returns
-; * RS_ERR_OVERFLOW if there is no space left in the transmit buffer.
-; */
-;
-
-_rs232_put:
- jsr CheckInitialized ; Check initialized
- bcc @L1
- rts
-
-; Try to send
-
-@L1: ldx SendFreeCnt
- cpx #$ff
- beq @L2
- pha
- lda #$00
- jsr TryToSend
- pla
-
-; Put byte into send buffer & send
-
-@L2: ldx SendFreeCnt
- bne @L3
- lda #ErrOverflow
- ldx #$00
- rts
-
-; There is enough room (character still in A)
-
-@L3: ldx IndReg
- ldy #BufferSeg ; Set indirect to buffer segment
- sty IndReg
- ldy SendTail
- sta (SendBuf),y
- stx IndReg ; Restore indirect bank
- inc SendTail
- dec SendFreeCnt
- lda #$ff
- jsr TryToSend
- lda #$00
- tax
- rts
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_pause (void);
-; /* Assert flow control and disable interrupts. */
-;
-
-_rs232_pause:
-; Check initialized
- jsr CheckInitialized
- bcc @L1
- rts
-
-; Assert flow control
-
-@L1: lda RtsOff
- sta Stopped
- jsr sys_bank ; Set indirect to system bank
- ldy #RegCommand
- sta (acia),y
-
-; Delay for flow stop to be received
-
- ldx BaudCode
- lda PauseTimes,x
- jsr DelayMs
-
-; Stop rx interrupts
-
- lda RtsOff
- ora #$02
- ldy #RegCommand
- sta (acia),y
- jsr restore_bank ; Restore indirect segment
- lda #0
- tax
- rts
-
-
-.rodata
-; Delay times: 32 byte-receive times in milliseconds, or 100 max.
-; Formula = 320,000 / baud
-PauseTimes:
- .byte 100,100,100,100,100,100,100,067,034,017,009,006,003,002,001,001
- ;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
-.code
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_unpause (void);
-; /* Re-enable interrupts and release flow control */
-;
-
-_rs232_unpause:
-; Check initialized
- jsr CheckInitialized
- bcc @L1
- rts
-
-; Re-enable rx interrupts & release flow control
-
-@L1: lda #$00
- sta Stopped
- lda RtsOff
- ora #%00001000
- ldx IndReg
- ldy #$0F
- sty IndReg ; Set indirect to system bank
- ldy #RegCommand
- sta (acia),y
- stx IndReg ; Restore indirect bank
-
-; Poll for stalled char & exit
-
- jsr PollReceive
- lda #0
- tax
- rts
-
-;----------------------------------------------------------------------------
-;
-; unsigned char __fastcall__ rs232_status (unsigned char* status,
-; unsigned char* errors);
-; /* Return the serial port status. */
-;
-
-_rs232_status:
- sta ptr2
- stx ptr2+1
- jsr popax
- sta ptr1
- stx ptr1+1
- jsr CheckInitialized
- bcs @L9
-
-; Get status
-
- ldx IndReg ; Save indirect segment
- lda #$0F
- sta IndReg ; Set system bank as indirect segment
- ldy #RegStatus
- lda (acia),y ; Read status register
- stx IndReg
- ldy #0
- sta (ptr1),y
- jsr PollReceive ; bug-recovery hack
- lda Errors
- ldy #0
- sta (ptr2),y
- tya
- tax
-@L9: rts
-
-;----------------------------------------------------------------------------
-;
-; RS232 interrupt handler.
-; The RS232 handler will be called with the system bank as indirect bank
-; and all registers saved.
-;
-
-k_rs232:
- ldy #RegStatus
- lda (acia),y ; check for byte received
- and #$08
- beq @L9 ; Nothing to receive
- lda (acia),y ; check for receive errors
- and #$07
- beq @L1
- inc Errors
-@L1: ldy #RegData
- lda (acia),y ; get byte and put into receive buffer
- ldx RecvFreeCnt
- beq @L3
- ldy #BufferSeg
- sty IndReg
- ldy RecvTail
- sta (RecvBuf),y ; Store received character
- lda #$0F
- sta IndReg ; Restore indirect segment
- inc RecvTail
- dec RecvFreeCnt
- cpx #33 ; check for buffer space low
- bcs @L9
-
-; Assert flow control
-
-@L2: lda RtsOff ; assert flow control if buffer space too low
- ldy #RegCommand
- sta (acia),y
- sta Stopped
- rts
-
-; Drop this char
-
-@L3: inc DropCnt+0 ;not time-critical
- bne @L9
- inc DropCnt+1
- bne @L9
- inc DropCnt+2
- bne @L9
- inc DropCnt+3
-@L9: rts
-
-
-;----------------------------------------------------------------------------
-;
-; CheckInitialized - internal check if initialized
-; Set carry and an error code if not initialized, clear carry and do not
-; change any registers if initialized.
-;
-
-CheckInitialized:
- bit Initialized
- bmi @L1
- lda #ErrNotInitialized
- ldx #0
- sec
- rts
-
-@L1: clc
- rts
-
-;----------------------------------------------------------------------------
-; Try to send a byte. Internal routine. A = TryHard
-
-TryToSend:
- sta tmp1 ; Remember tryHard flag
- ldx IndReg ; Save indirect segment
- lda #$0F
- sta IndReg ; Set system segment as indirect segment
-@L0: lda SendFreeCnt
- cmp #$ff
- beq @L3 ; Bail out
-
-; Check for flow stopped
-
-@L1: lda Stopped
- bne @L3 ; Bail out
-
-; Check that the UART is ready to send
-
-@L2: ldy #RegStatus
- lda (acia),y
- and #$10
- bne @L4
- bit tmp1 ; Keep trying if must try hard
- bmi @L0
-@L3: stx IndReg ; Restore indirect segment
- rts
-
-; Send byte and try again
-
-@L4: lda #BufferSeg
- sta IndReg
- ldy SendHead
- lda (SendBuf),y
- ldy #$0F
- sty IndReg
- ldy #RegData
- sta (acia),y
- inc SendHead
- inc SendFreeCnt
- jmp @L0
-
-
-;----------------------------------------------------------------------------
-;
-; 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.
-;
-
-PollReceive:
- ldx IndReg ; Save indirect segment
- lda #$0F
- sta IndReg ; Set system bank as indirect segment
- ldy #RegStatus
- lda (acia),y
- and #$08
- beq @L9
- lda (acia),y ; Read a second time? ###
- and #$08
- beq @L9
- ldy #RegData
- lda (acia),y
- ldy RecvFreeCnt
- beq @L9
- ldy #BufferSeg
- sty IndReg
- ldy RecvTail
- sta (RecvBuf),y
- inc RecvTail
- dec RecvFreeCnt
-@L9: stx IndReg ; Restore indirect segment
- rts
-
-;----------------------------------------------------------------------------
-;
-; 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:
-; repeat for number of MHz of cpu speed:
-; delay for 1017 clock cycles
-;
-
-DelayMs: ;( .A=milliseconds )
-@L1: ldy #2 ; 2MHz
-@L2: ldx #203 ;(2)
-@L3: dex ;(2)
- bne @L3 ;(3) // 1017 cycles
- dey
- bne @L2
- sec
- sbc #1
- bne @L1
- rts
-
-.end
-
-
-
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