mirror of
https://github.com/cc65/cc65.git
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Added first version of swiftlink driver
git-svn-id: svn://svn.cc65.org/cc65/trunk@2321 b7a2c559-68d2-44c3-8de9-860c34a00d81
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683
libsrc/c64/c64-swlink.s
Normal file
683
libsrc/c64/c64-swlink.s
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;
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; Serial driver for the C64 using a Swiftlink or Turbo-232 cartridge.
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;
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; Ullrich von Bassewitz, 2003-04-18
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;
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; The driver is based on the cc65 rs232 module, which in turn is based on
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; Craig Bruce device driver for the Switftlink/Turbo-232.
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;
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; SwiftLink/Turbo-232 v0.90 device driver, by Craig Bruce, 14-Apr-1998.
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;
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; This software is Public Domain. It is in Buddy assembler format.
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;
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; This device driver uses the SwiftLink RS-232 Serial Cartridge, available from
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; Creative Micro Designs, Inc, and also supports the extensions of the Turbo232
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; Serial Cartridge. Both devices are based on the 6551 ACIA chip. It also
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; supports the "hacked" SwiftLink with a 1.8432 MHz crystal.
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;
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; The code assumes that the kernal + I/O are in context. On the C128, call
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; it from Bank 15. On the C64, don't flip out the Kernal unless a suitable
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; NMI catcher is put into the RAM under then Kernal. For the SuperCPU, the
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; interrupt handling assumes that the 65816 is in 6502-emulation mode.
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;
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.include "zeropage.inc"
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.include "ser-kernel.inc"
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.include "ser-error.inc"
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.include "c64.inc"
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; ------------------------------------------------------------------------
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; Header. Includes jump table
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.segment "JUMPTABLE"
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; Driver signature
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.byte $73, $65, $72 ; "ser"
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.byte $00 ; Serial API version number
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; Jump table.
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.word INSTALL
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.word UNINSTALL
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.word PARAMS
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.word GET
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.word PUT
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.word PAUSE
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.word UNPAUSE
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.word STATUS
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.word IOCTL
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;----------------------------------------------------------------------------
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; I/O definitions
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ACIA = $DE00
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ACIA_DATA = ACIA+0 ; Data register
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ACIA_STATUS = ACIA+1 ; Status register
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ACIA_CMD = ACIA+2 ; Command register
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ACIA_CTRL = ACIA+3 ; Control register
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ACIA_CLOCK = ACIA+7 ; Turbo232 external baud-rate generator
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;----------------------------------------------------------------------------
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;
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; Global variables
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;
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.bss
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DropCnt: .res 4 ; Number of bytes lost from rx buffer full
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Stopped: .res 1 ; Flow-stopped flag
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RtsOff: .res 1 ;
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Errors: .res 1 ; Number of bytes received in error, low byte
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RecvHead: .res 1 ; Head of receive buffer
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RecvTail: .res 1 ; Tail of receive buffer
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RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
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SendHead: .res 1 ; Head of send buffer
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SendTail: .res 1 ; Tail of send buffer
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SendFreeCnt: .res 1 ; Number of bytes free in send buffer
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BaudCode: .res 1 ; Current baud in effect
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; Send and receive buffers: 256 bytes each
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RecvBuf: .res 256
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SendBuf: .res 256
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.data
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NmiContinue: .byte $4c ; JMP instruction for NMI save -- continue
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NmiSave: .res 2 ; normal NMI handler
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.rodata
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; Tables used to translate RS232 params into register values
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BaudTable: ; bit7 = 1 means setting is invalid
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.byte $FF ; SER_BAUD_45_5
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.byte $FF ; SER_BAUD_50
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.byte $FF ; SER_BAUD_75
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.byte $FF ; SER_BAUD_110
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.byte $FF ; SER_BAUD_134_5
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.byte $FF ; SER_BAUD_150
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.byte $05 ; SER_BAUD_300
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.byte $06 ; SER_BAUD_600
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.byte $07 ; SER_BAUD_1200
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.byte $FF ; SER_BAUD_1800
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.byte $08 ; SER_BAUD_2400
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.byte $FF ; SER_BAUD_3600
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.byte $0A ; SER_BAUD_4800
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.byte $FF ; SER_BAUD_7200
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.byte $0C ; SER_BAUD_9600
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.byte $0E ; SER_BAUD_19200
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.byte $0F ; SER_BAUD_38400
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.byte $FF ; SER_BAUD_57600
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.byte $FF ; SER_BAUD_115200
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.byte $FF ; SER_BAUD_230400
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BitTable:
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.byte $60 ; SER_BITS_5
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.byte $40 ; SER_BITS_6
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.byte $20 ; SER_BITS_7
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.byte $00 ; SER_BITS_8
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StopTable:
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.byte $00 ; SER_STOP_1
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.byte $80 ; SER_STOP_2
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ParityTable:
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.byte $00 ; SER_PAR_NONE
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.byte $20 ; SER_PAR_ODD
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.byte $60 ; SER_PAR_EVEN
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.byte $A0 ; SER_PAR_MARK
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.byte $E0 ; SER_PAR_SPACE
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HandshakeTable: ; bit7 = 1 means that setting is invalid
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.byte $FF ; SER_HS_NONE
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.byte $00 ; SER_HS_HW
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.byte $FF ; SER_HS_SW
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; Delay times: 32 byte-receive times in milliseconds, or 100 max.
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; Formula = 320,000 / baud. Invalid values do contain $FF.
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PauseTimes:
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.byte $FF ; SER_BAUD_45_5
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.byte $FF ; SER_BAUD_50
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.byte $FF ; SER_BAUD_75
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.byte $FF ; SER_BAUD_110
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.byte $FF ; SER_BAUD_134_5
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.byte $FF ; SER_BAUD_150
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.byte 100 ; SER_BAUD_300
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.byte 100 ; SER_BAUD_600
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.byte 100 ; SER_BAUD_1200
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.byte $FF ; SER_BAUD_1800
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.byte 100 ; SER_BAUD_2400
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.byte $FF ; SER_BAUD_3600
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.byte 67 ; SER_BAUD_4800
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.byte $FF ; SER_BAUD_7200
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.byte 34 ; SER_BAUD_9600
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.byte 17 ; SER_BAUD_19200
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.byte 9 ; SER_BAUD_38400
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.byte $FF ; SER_BAUD_57600
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.byte $FF ; SER_BAUD_115200
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.byte $FF ; SER_BAUD_230400
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.code
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;----------------------------------------------------------------------------
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; INSTALL routine. Is called after the driver is loaded into memory. If
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; possible, check if the hardware is present.
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; Must return an SER_ERR_xx code in a/x.
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INSTALL:
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; Initialize buffers & control
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@L4: lda #0
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sta RecvHead
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sta SendHead
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sta RecvTail
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sta SendTail
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sta Errors
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sta Stopped
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lda #255
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sta RecvFreeCnt
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sta SendFreeCnt
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; Set up nmi's
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lda NMIVec
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ldy NMIVec+1
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sta NmiSave+0
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sty NmiSave+1
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lda #<NmiHandler
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ldy #>NmiHandler
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sta NMIVec
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sty NMIVec+1
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; Set default to 2400-8N1, enable interrupts
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lda ACIA_DATA
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lda ACIA_STATUS
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lda #$18
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sta ACIA_CTRL
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lda #$01
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sta RtsOff
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ora #$08
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sta ACIA_CMD
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lda #$06
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sta BaudCode
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; Done, return an error code
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lda #SER_ERR_OK
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tax
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rts
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;----------------------------------------------------------------------------
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; UNINSTALL routine. Is called before the driver is removed from memory.
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; Must return an SER_ERR_xx code in a/x.
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UNINSTALL:
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; Stop interrupts, drop DTR
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lda RtsOff
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and #%11100010
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ora #%00000010
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sta ACIA_CMD
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; Restore NMI vector
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lda NmiSave+0
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ldy NmiSave+1
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sta NMIVec
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sty NMIVec+1
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; Flag uninitialized
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lda #SER_ERR_OK
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tax
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rts
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;----------------------------------------------------------------------------
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; PARAMS routine. A pointer to a ser_params structure is passed in ptr1.
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; Must return an SER_ERR_xx code in a/x.
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PARAMS:
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ldy #SER_PARAMS_BAUDRATE
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lda (ptr1),y ; Baudrate index
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tax
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lda BaudTable,x ; Get 6551 value
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bmi invalid ; Branch if rate not supported
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sta tmp1
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iny ; Databits
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lda (ptr1),y
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tax
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lda BitTable,x
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ora tmp1
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sta tmp1
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iny ; Stopbits
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lda (ptr1),y
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tax
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lda StopTable,x
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ora tmp1
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sta tmp1
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iny ; Parity
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lda (ptr1),y
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tax
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lda ParityTable,x
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ora tmp1
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sta tmp1
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iny ; Handshake
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lda (ptr1),y
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tax
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lda HandshakeTable,x
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bmi invalid
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;----------------------------------------------------------------------------
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;
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; unsigned char __fastcall__ rs232_params (unsigned char params, unsigned char parity);
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; /* Set the port parameters. Use a combination of the #defined values above. */
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;
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; Set communication parameters.
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;
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; baud rates stops word | parity
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; --------------------- ----- ----- | ---------
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; $00=50 $08=9600 $00=1 $00=8 | $00=none
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; $01=110 $09=19200 $80=2 $20=7 | $20=odd
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; $02=134.5 $0a=38400 $40=6 | $60=even
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; $03=300 $0b=57600 $60=5 | $A0=mark
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; $04=600 $0c=115200 | $E0=space
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; $05=1200 $0d=230400
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; $06=2400 $0e=future
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; $07=4800 $0f=future
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;
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_rs232_params:
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and #%11100000 ; Save new parity
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ora #%00000001
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sta tmp2
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; Check cpu speed against baud rate
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jsr popa
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sta tmp1
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and #$0f
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cmp #$0c
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bcc @L3
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ldx CpuSpeed ; ###
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cpx #1+1
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bcc @L2
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cmp #$0c
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beq @L3
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cpx #4
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bcs @L3
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@L2: lda #RS_ERR_BAUD_TOO_FAST
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bne @L9
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; Set baud/parameters
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@L3: lda tmp1
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and #$0f
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tax
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lda BaudTable,x
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cmp #$ff
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bne @L5
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lda #RS_ERR_BAUD_NOT_AVAIL
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bne @L9
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@L5: tax
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and #$30
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beq @L6
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bit Turbo232
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bmi @L6
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lda #RS_ERR_BAUD_NOT_AVAIL
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bne @L9
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@L6: lda tmp1
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and #$0f
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sta BaudCode
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lda tmp1
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and #%11100000
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ora #%00010000
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sta tmp1
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txa
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and #$0f
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ora tmp1
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sta ACIA_CTRL
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txa
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and #%00110000
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beq @L7
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lsr
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lsr
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lsr
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lsr
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eor #%00000011
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sta ACIA_CLOCK
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; Set new parity
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@L7: lda tmp2
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sta RtsOff
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ora #%00001000
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sta ACIA_CMD
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lda #0
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@L9: ldx #0
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rts
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.rodata
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BaudTable:
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.byte $ff,$ff,$ff,$05,$06,$07,$08,$0a,$0c,$0e,$0f,$10,$20,$30,$ff,$ff
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;in: 0 1 2 3 4 5 6 7 8 9 a b c d e f
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;baud50 110 134 3 6 12 24 48 96 19 38 57 115 230 exp exp
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;out masks: $0F=Baud, val$FF=err
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; $30=t232ExtBaud: $00=none, $10=57.6, $20=115.2, $30=230.4
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.code
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;----------------------------------------------------------------------------
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; GET: Will fetch a character from the receive buffer and store it into the
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; variable pointer to by ptr1. If no data is available, SER_ERR_NO_DATA is
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; return.
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;
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GET:
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; Check for bytes to send
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ldx SendFreeCnt
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cpx #$ff
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beq @L1
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lda #$00
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jsr TryToSend
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; Check for buffer empty
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@L1: lda RecvFreeCnt ; (25)
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cmp #$ff
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bne @L2
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lda #SER_ERR_NO_DATA
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ldx #0
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rts
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; Check for flow stopped & enough free: release flow control
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@L2: ldx Stopped ; (34)
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beq @L3
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cmp #63
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bcc @L3
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lda #$00
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sta Stopped
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lda RtsOff
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ora #%00001000
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sta ACIA_CMD
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; Get byte from buffer
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@L3: ldx RecvHead ; (41)
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lda RecvBuf,x
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inc RecvHead
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inc RecvFreeCnt
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ldx #$00 ; (59)
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sta (ptr1,x)
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txa ; Return code = 0
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rts
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;----------------------------------------------------------------------------
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; PUT: Output character in A.
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; Must return an error code in a/x.
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;
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PUT:
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; Try to send
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ldx SendFreeCnt
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cpx #$ff
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beq @L2
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pha
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lda #$00
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jsr TryToSend
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pla
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; Put byte into send buffer & send
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@L2: ldx SendFreeCnt
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bne @L3
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lda #<SER_ERR_OVERFLOW ; X is already zero
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rts
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@L3: ldx SendTail
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sta SendBuf,x
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inc SendTail
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dec SendFreeCnt
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lda #$ff
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jsr TryToSend
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lda #<SER_ERR_OK
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tax
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rts
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;----------------------------------------------------------------------------
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; PAUSE: Assert flow control and disable interrupts.
|
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; Must return an error code in a/x.
|
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;
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PAUSE:
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; Assert flow control
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lda RtsOff
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sta Stopped
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sta ACIA_CMD
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; Delay for flow stop to be received
|
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ldx BaudCode
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ldy PauseTimes,x
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jsr DelayMs
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; Stop rx interrupts
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lda RtsOff
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ora #$02
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sta ACIA_CMD
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lda #<SER_ERR_OK
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tax
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rts
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|
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;----------------------------------------------------------------------------
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; UNPAUSE: Re-enable interrupts and release flow control.
|
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; Must return an error code in a/x.
|
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;
|
||||
|
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UNPAUSE:
|
||||
|
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; Re-enable rx interrupts & release flow control
|
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|
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@L1: lda #$00
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sta Stopped
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lda RtsOff
|
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ora #%00001000
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sta ACIA_CMD
|
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|
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; Poll for stalled char & exit
|
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|
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jsr PollReceive
|
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lda #<SER_ERR_OK
|
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tax
|
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rts
|
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|
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;----------------------------------------------------------------------------
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||||
; STATUS: Return the status in the variable pointed to by ptr1.
|
||||
; Must return an error code in a/x.
|
||||
;
|
||||
|
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STATUS:
|
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|
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; Get status
|
||||
|
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lda ACIA_STATUS
|
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ldy #0
|
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sta (ptr1),y
|
||||
jsr PollReceive ; bug-recovery hack
|
||||
tya ; SER_ERR_OK
|
||||
tax
|
||||
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!
|
||||
;
|
||||
|
||||
NmiHandler:
|
||||
pha
|
||||
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 #$07 ;(2) opt
|
||||
beq @L1 ;(3*)opt
|
||||
inc Errors ;(5^)opt
|
||||
@L1: lda ACIA_DATA ;(4) ;data ;get byte and put into receive buffer
|
||||
ldy RecvTail ;(4)
|
||||
ldx RecvFreeCnt ;(4)
|
||||
beq @L3 ;(2*)
|
||||
sta RecvBuf,y ;(5)
|
||||
inc RecvTail ;(6)
|
||||
dec RecvFreeCnt ;(6)
|
||||
cpx #33 ;(2) ;check for buffer space low
|
||||
bcc @L2 ;(2*)
|
||||
jmp NMIEXIT ;(3)
|
||||
|
||||
; Assert flow control
|
||||
|
||||
@L2: lda RtsOff ;(3) ;assert flow control if buffer space too low
|
||||
sta ACIA_CMD ;(4) ;command
|
||||
sta Stopped ;(3)
|
||||
jmp NMIEXIT ;(3)
|
||||
|
||||
; Drop this char
|
||||
|
||||
@L3: inc DropCnt+0 ; not time-critical
|
||||
bne @L4
|
||||
inc DropCnt+1
|
||||
bne @L4
|
||||
inc DropCnt+2
|
||||
bne @L4
|
||||
inc DropCnt+3
|
||||
@L4: jmp NMIEXIT
|
||||
|
||||
@L9: pla
|
||||
jmp NmiContinue
|
||||
|
||||
;----------------------------------------------------------------------------
|
||||
; Try to send a byte. Internal routine. A = TryHard
|
||||
|
||||
.proc TryToSend
|
||||
|
||||
sta tmp1 ; Remember tryHard flag
|
||||
@L0: lda SendFreeCnt
|
||||
cmp #$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
|
||||
|
||||
;----------------------------------------------------------------------------
|
||||
;
|
||||
; 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
|
||||
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user