mirror of
https://github.com/cc65/cc65.git
synced 2024-10-31 04:04:49 +00:00
670 lines
15 KiB
ArmAsm
670 lines
15 KiB
ArmAsm
;
|
|
; 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
|
|
.import popa, popax
|
|
.export _rs232_init, _rs232_params, _rs232_done, _rs232_get
|
|
.export _rs232_put, _rs232_pause, _rs232_unpause, _rs232_status
|
|
|
|
.include "c128.inc"
|
|
.include "rs232.inc"
|
|
|
|
|
|
NmiExit = $ff33 ;exit address for nmi
|
|
|
|
ACIA = $DE00
|
|
|
|
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; 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
|
|
Turbo232: .res 1 ; Flag indicating turbo-232
|
|
HackedFlag: .res 1 ; Flag indicating hacked-crystal swiftlink
|
|
CpuSpeed: .res 1 ; In MHz
|
|
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
|
|
|
|
; Switftlink register offsets
|
|
RegData = 0 ; Data register
|
|
RegStatus = 1 ; Status register
|
|
RegCommand = 2 ; Command register
|
|
RegControl = 3 ; Control register
|
|
RegClock = 7 ; Turbo232 external baud-rate generator
|
|
|
|
|
|
|
|
.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
|
|
|
|
;** set hacked-crystal
|
|
|
|
@L1: sta HackedFlag
|
|
|
|
;** check for turbo-232
|
|
|
|
lda #$00
|
|
sta ACIA+RegControl
|
|
tax
|
|
lda ACIA+RegClock
|
|
beq @L3
|
|
dex
|
|
@L3: stx Turbo232
|
|
|
|
;** get C128 cpu speed
|
|
|
|
lda $d030
|
|
and #$01
|
|
clc
|
|
adc #1
|
|
sta CpuSpeed
|
|
|
|
;** check for super-cpu at 20 MHz
|
|
|
|
bit SCPU_Detect
|
|
bmi @L4
|
|
bit $d0b8
|
|
bvs @L4
|
|
lda #20
|
|
sta CpuSpeed
|
|
|
|
;** 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+RegData
|
|
lda ACIA+RegStatus
|
|
lda #$18
|
|
bit HackedFlag
|
|
bpl @L5
|
|
lda #$1a
|
|
@L5: sta ACIA+RegControl
|
|
|
|
lda #$01
|
|
sta RtsOff
|
|
ora #$08
|
|
sta ACIA+RegCommand
|
|
lda #$06
|
|
sta BaudCode
|
|
|
|
; Done
|
|
|
|
ldx #$ff
|
|
stx Initialized
|
|
inx ; X = 0
|
|
txa ; A = 0
|
|
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:
|
|
bit Initialized
|
|
bmi @L1
|
|
jmp NotInitialized ; Return an error code
|
|
|
|
; Save new parity
|
|
|
|
@L1: and #%11100000
|
|
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 #$0f
|
|
tax
|
|
lda NormBauds,x
|
|
bit HackedFlag
|
|
bpl @L4
|
|
lda HackBauds,x
|
|
@L4: cmp #$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+RegControl
|
|
txa
|
|
and #%00110000
|
|
beq @L7
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
eor #%00000011
|
|
sta ACIA+RegClock
|
|
|
|
; Set new parity
|
|
|
|
@L7: lda tmp2
|
|
sta RtsOff
|
|
ora #%00001000
|
|
sta ACIA+RegCommand
|
|
lda #0
|
|
@L9: ldx #0
|
|
rts
|
|
|
|
.rodata
|
|
|
|
NormBauds:
|
|
.byte $ff,$ff,$ff,$05,$06,$07,$08,$0a,$0c,$0e,$0f,$10,$20,$30,$ff,$ff
|
|
HackBauds:
|
|
.byte $01,$03,$04,$06,$07,$08,$0a,$0c,$0e,$0f,$ff,$ff,$00,$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
|
|
; $30=t232ExtBaud: $00=none, $10=57.6, $20=115.2, $30=230.4
|
|
.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
|
|
sta ACIA+RegCommand
|
|
|
|
; Restore NMI vector
|
|
|
|
lda NmiSave+0
|
|
ldy NmiSave+1
|
|
sta NMIVec
|
|
sty NMIVec+1
|
|
|
|
; Flag uninitialized
|
|
|
|
@L9: lda #$00
|
|
sta Initialized
|
|
tax
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; unsigned char __fastcall__ rs232_get (char* B);
|
|
; /* Get a character from the serial port. If no characters are available, the
|
|
; * function will return RS_ERR_NO_DATA, so this is not a fatal error.
|
|
; */
|
|
;
|
|
|
|
_rs232_get:
|
|
bit Initialized
|
|
bpl NotInitialized ; Jump if not initialized
|
|
|
|
; Check for bytes to send
|
|
|
|
@L1: sta ptr1
|
|
stx ptr1+1 ; Store pointer to received char
|
|
ldx SendFreeCnt
|
|
cpx #$ff
|
|
beq @L2
|
|
lda #$00
|
|
jsr TryToSend
|
|
|
|
; Check for buffer empty
|
|
|
|
@L2: lda RecvFreeCnt
|
|
cmp #$ff
|
|
bne @L3
|
|
lda #RS_ERR_NO_DATA
|
|
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
|
|
sta ACIA+RegCommand
|
|
|
|
; Get byte from buffer
|
|
|
|
@L4: ldx RecvHead
|
|
lda RecvBuf,x
|
|
inc RecvHead
|
|
inc RecvFreeCnt
|
|
ldx #$00
|
|
sta (ptr1,x)
|
|
txa ; Return code = 0
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; RS232 module not initialized
|
|
|
|
NotInitialized:
|
|
lda #<RS_ERR_NOT_INITIALIZED
|
|
ldx #>RS_ERR_NOT_INITIALIZED
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; unsigned char __fastcall__ rs232_put (char B);
|
|
; /* Send a character via the serial port. There is a transmit buffer, but
|
|
; * transmitting is not done via interrupt. The function returns
|
|
; * RS_ERR_OVERFLOW if there is no space left in the transmit buffer.
|
|
; */
|
|
;
|
|
|
|
_rs232_put:
|
|
bit Initialized
|
|
bpl NotInitialized ; Jump if not initialized
|
|
|
|
; Try to send
|
|
|
|
@L1: ldx SendFreeCnt
|
|
cpx #$ff
|
|
beq @L2
|
|
pha
|
|
lda #$00
|
|
jsr TryToSend
|
|
pla
|
|
|
|
; Put byte into send buffer & send
|
|
|
|
@L2: ldx SendFreeCnt
|
|
bne @L3
|
|
lda #RS_ERR_OVERFLOW
|
|
ldx #$00
|
|
rts
|
|
|
|
@L3: ldx SendTail
|
|
sta SendBuf,x
|
|
inc SendTail
|
|
dec SendFreeCnt
|
|
lda #$ff
|
|
jsr TryToSend
|
|
lda #$00
|
|
tax
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; unsigned char __fastcall__ rs232_pause (void);
|
|
; /* Assert flow control and disable interrupts. */
|
|
;
|
|
|
|
_rs232_pause:
|
|
bit Initialized
|
|
bpl NotInitialized ; Jump if not initialized
|
|
|
|
; Assert flow control
|
|
|
|
@L1: lda RtsOff
|
|
sta Stopped
|
|
sta ACIA+RegCommand
|
|
|
|
; Delay for flow stop to be received
|
|
|
|
ldx BaudCode
|
|
lda PauseTimes,x
|
|
jsr DelayMs
|
|
|
|
; Stop rx interrupts
|
|
|
|
lda RtsOff
|
|
ora #$02
|
|
sta ACIA+RegCommand
|
|
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:
|
|
bit Initialized
|
|
bpl NotInitialized ; Jump if not initialized
|
|
|
|
; Re-enable rx interrupts & release flow control
|
|
|
|
@L1: lda #$00
|
|
sta Stopped
|
|
lda RtsOff
|
|
ora #%00001000
|
|
sta ACIA+RegCommand
|
|
|
|
; 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
|
|
bit Initialized
|
|
bmi @L1
|
|
jmp NotInitialized
|
|
|
|
; Get status
|
|
|
|
@L1: lda ACIA+RegStatus
|
|
ldy #0
|
|
sta (ptr1),y
|
|
jsr PollReceive ; bug-recovery hack
|
|
lda Errors
|
|
sta (ptr2),y
|
|
tya
|
|
tax
|
|
@L9: 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!
|
|
;
|
|
; Because of the C128 banking, the NMI handler must go into the non banked
|
|
; memory, since the ROM NMI entry point will switch to a configuration where
|
|
; only the lowest 16K of RAM are visible. We will place the NMI handler into
|
|
; the LOWCODE segment and map this segment into the lower 16K in the linker
|
|
; config.
|
|
|
|
.segment "LOWCODE"
|
|
|
|
NmiHandler:
|
|
lda #CC65_MMU_CFG ;(2)
|
|
sta MMU_CR ;(4)
|
|
lda ACIA+RegStatus ;(4) ;status ;check for byte received
|
|
and #$08 ;(2)
|
|
beq @L9 ;(2*)
|
|
lda ACIA+RegStatus ;(4) opt ;status ;check for receive errors
|
|
and #$07 ;(2) opt
|
|
beq @L1 ;(3*)opt
|
|
inc Errors ;(5^)opt
|
|
@L1: lda ACIA+RegData ;(4) ;data ;get byte and put into receive buffer
|
|
ldy RecvTail ;(4)
|
|
ldx RecvFreeCnt ;(4)
|
|
beq @L3 ;(2*)
|
|
sta RecvBuf,y ;(5)
|
|
inc RecvTail ;(6)
|
|
dec RecvFreeCnt ;(6)
|
|
cpx #33 ;(2) ;check for buffer space low
|
|
bcc @L2 ;(2*)
|
|
jmp NmiExit ;(3)
|
|
|
|
; Assert flow control
|
|
|
|
@L2: lda RtsOff ;(3) ;assert flow control if buffer space too low
|
|
sta ACIA+RegCommand ;(4) ;command
|
|
sta Stopped ;(3)
|
|
jmp NmiExit ;(3)
|
|
|
|
; Drop this char
|
|
|
|
@L3: inc DropCnt+0 ;not time-critical
|
|
bne @L4
|
|
inc DropCnt+1
|
|
bne @L4
|
|
inc DropCnt+2
|
|
bne @L4
|
|
inc DropCnt+3
|
|
@L4: jmp NmiExit
|
|
|
|
@L9: jmp NmiContinue
|
|
|
|
|
|
.code
|
|
|
|
;----------------------------------------------------------------------------
|
|
; Try to send a byte. Internal routine. A = TryHard
|
|
|
|
TryToSend:
|
|
sta tmp1 ; Remember tryHard flag
|
|
@L0: lda SendFreeCnt
|
|
cmp #$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+RegStatus
|
|
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+RegData
|
|
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:
|
|
lda #$08
|
|
and ACIA+RegStatus
|
|
beq @L9
|
|
and ACIA+RegStatus
|
|
beq @L9
|
|
lda ACIA+RegData
|
|
ldx RecvFreeCnt
|
|
beq @L9
|
|
ldx RecvTail
|
|
sta RecvBuf,x
|
|
inc RecvTail
|
|
dec RecvFreeCnt
|
|
@L9: 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 CpuSpeed
|
|
@L2: ldx #203 ;(2)
|
|
@L3: dex ;(2)
|
|
bne @L3 ;(3) // 1017 cycles
|
|
dey
|
|
bne @L2
|
|
sec
|
|
sbc #1
|
|
bne @L1
|
|
rts
|
|
|
|
.end
|
|
|
|
|
|
|