mirror of
https://github.com/cc65/cc65.git
synced 2024-12-23 04:30:10 +00:00
499 lines
14 KiB
ArmAsm
499 lines
14 KiB
ArmAsm
;
|
|
; Serial driver for the C128 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 "c128.inc"
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Header. Includes jump table
|
|
|
|
.segment "JUMPTABLE"
|
|
|
|
; Driver signature
|
|
|
|
.byte $73, $65, $72 ; "ser"
|
|
.byte SER_API_VERSION ; Serial API version number
|
|
|
|
; Jump table.
|
|
|
|
.word INSTALL
|
|
.word UNINSTALL
|
|
.word OPEN
|
|
.word CLOSE
|
|
.word GET
|
|
.word PUT
|
|
.word STATUS
|
|
.word IOCTL
|
|
.word IRQ
|
|
|
|
;----------------------------------------------------------------------------
|
|
; 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
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; Global variables
|
|
;
|
|
|
|
; We reuse the RS232 zero page variables for the driver, since the ROM
|
|
; routines cannot be used together with this driver (may also use $A0F
|
|
; and following in case of problems).
|
|
RecvHead := $A7 ; Head of receive buffer
|
|
RecvTail := $A8 ; Tail of receive buffer
|
|
RecvFreeCnt := $A9 ; Number of bytes in receive buffer
|
|
SendHead := $AA ; Head of send buffer
|
|
SendTail := $AB ; Tail of send buffer
|
|
SendFreeCnt := $B4 ; Number of bytes free in send buffer
|
|
Stopped := $B5 ; Flow-stopped flag
|
|
RtsOff := $B6 ;
|
|
|
|
; Send and receive buffers: 256 bytes each
|
|
RecvBuf := $0C00 ; Use the ROM buffers
|
|
SendBuf := $0D00
|
|
|
|
.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 $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 $09 ; SER_BAUD_3600
|
|
.byte $0A ; SER_BAUD_4800
|
|
.byte $0B ; 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
|
|
|
|
.code
|
|
|
|
;----------------------------------------------------------------------------
|
|
; Interrupt stub that is copied into low RAM. The startup code uses a special
|
|
; memory configuration with just kernal and I/O enabled (anything else is RAM).
|
|
; The NMI handler in ROM will switch back to a configuration where just the
|
|
; low 16K RAM are accessible. So we have to copy a smal piece of code into
|
|
; low RAM that enables the cc65 configuration and then jumps to the real NMI
|
|
; handler.
|
|
|
|
NmiStubOrig := *
|
|
|
|
.org $1150 ; BASIC graphics area
|
|
.proc NmiStub
|
|
|
|
lda #MMU_CFG_CC65 ; Bank 0 with kernal ROM...
|
|
sta MMU_CR ; ...enable
|
|
jsr NmiHandler ; Call the actual NMI handler
|
|
lda #$00 ; Get ROM config...
|
|
sta MMU_CR ; ...and enable it
|
|
Vector := *+1
|
|
.byte $4C ; Jump to the saved IRQ vector
|
|
|
|
.endproc
|
|
.reloc
|
|
|
|
;----------------------------------------------------------------------------
|
|
; 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:
|
|
|
|
; Deactivate DTR and disable 6551 interrupts
|
|
|
|
lda #%00001010
|
|
sta ACIA_CMD
|
|
|
|
; Copy the NMI stub into low memory
|
|
|
|
ldy #.sizeof (NmiStub)-1
|
|
@L1: lda NmiStubOrig,y
|
|
sta NmiStub,y
|
|
dey
|
|
bpl @L1
|
|
|
|
; Set up the nmi vector
|
|
|
|
lda NMIVec
|
|
ldy NMIVec+1
|
|
sta NmiStub::Vector+0
|
|
sty NmiStub::Vector+1
|
|
lda #<NmiStub
|
|
ldy #>NmiStub
|
|
SetNMI: sta NMIVec
|
|
sty NMIVec+1
|
|
|
|
; Done, return an error code
|
|
|
|
lda #<SER_ERR_OK
|
|
tax ; A is zero
|
|
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 #%00001010
|
|
sta ACIA_CMD
|
|
|
|
; Restore NMI vector and return OK
|
|
|
|
lda NmiStub::Vector+0
|
|
ldy NmiStub::Vector+1
|
|
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.
|
|
|
|
OPEN:
|
|
|
|
; 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
|
|
|
|
; 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
|
|
|
|
ldy #SER_PARAMS::DATABITS ; Databits
|
|
lda (ptr1),y
|
|
tay
|
|
lda BitTable,y
|
|
ora tmp1
|
|
sta tmp1
|
|
|
|
ldy #SER_PARAMS::STOPBITS ; Stopbits
|
|
lda (ptr1),y
|
|
tay
|
|
lda StopTable,y
|
|
ora tmp1
|
|
ora #%00010000 ; Receiver clock source = baudrate
|
|
sta ACIA_CTRL
|
|
|
|
; 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
|
|
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.
|
|
;
|
|
|
|
CLOSE:
|
|
|
|
; Stop interrupts, drop DTR
|
|
|
|
lda #%00001010
|
|
sta ACIA_CMD
|
|
|
|
; Initalize buffers. Returns zero in a
|
|
|
|
jsr InitBuffers
|
|
|
|
; Return OK
|
|
|
|
lda #<SER_ERR_OK
|
|
tax ; A is zero
|
|
rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; 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: ldx SendFreeCnt ; Send data if necessary
|
|
inx ; X == $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 #>SER_ERR_NO_DATA
|
|
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
|
|
inx ; X = $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
|
|
|
|
;----------------------------------------------------------------------------
|
|
; STATUS: Return the status in the variable pointed to by ptr1.
|
|
; Must return an error code in a/x.
|
|
;
|
|
|
|
STATUS: lda ACIA_STATUS
|
|
ldx #0
|
|
sta (ptr1,x)
|
|
txa ; SER_ERR_OK
|
|
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
|
|
|
|
;----------------------------------------------------------------------------
|
|
; IRQ: Not used on the C128
|
|
;
|
|
|
|
IRQ = $0000
|
|
|
|
;----------------------------------------------------------------------------
|
|
;
|
|
; 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!
|
|
;
|
|
; Note: Because of the C128 banking, a small stub has to go into low memory,
|
|
; since the ROM NMI entry point switches to a configuration, where only the
|
|
; low 16K of RAM are visible. The entry code switches into the standard cc65
|
|
; configuration (I/O + 16K kernal) and then jumps here. Registers are already
|
|
; saved by the ROM code.
|
|
|
|
NmiHandler:
|
|
lda ACIA_STATUS ;(4) ;status ;check for byte received
|
|
and #$08 ;(2)
|
|
beq @L9 ;(2*)
|
|
cld
|
|
lda ACIA_DATA ;(4) data ;get byte and put into receive buffer
|
|
ldy RecvTail ;(4)
|
|
ldx RecvFreeCnt ;(4)
|
|
beq @L9 ;(2*) Jump if no space in receive buffer
|
|
sta RecvBuf,y ;(5)
|
|
inc RecvTail ;(6)
|
|
dec RecvFreeCnt ;(6)
|
|
cpx #33 ;(2) check for buffer space low
|
|
bcc @L2 ;(2*)
|
|
rts
|
|
|
|
; Assert flow control
|
|
|
|
@L2: lda RtsOff ;(3) assert flow control if buffer space too low
|
|
sta ACIA_CMD ;(4) command
|
|
sta Stopped ;(3)
|
|
@L9: rts
|
|
|
|
;----------------------------------------------------------------------------
|
|
; Try to send a byte. Internal routine. A = TryHard
|
|
|
|
.proc TryToSend
|
|
|
|
sta tmp1 ; Remember tryHard flag
|
|
@L0: lda SendFreeCnt
|
|
cmp #$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
|
|
|
|
|
|
;----------------------------------------------------------------------------
|
|
; Initialize buffers
|
|
|
|
InitBuffers:
|
|
ldx #0
|
|
stx Stopped
|
|
stx RecvHead
|
|
stx RecvTail
|
|
stx SendHead
|
|
stx SendTail
|
|
dex ; X = 255
|
|
stx RecvFreeCnt
|
|
stx SendFreeCnt
|
|
rts
|
|
|
|
|