2 ; Serial driver for the Apple II Super Serial Card.
4 ; Oliver Schmidt, 21.04.2005
6 ; The driver is based on the cc65 rs232 module, which in turn is based on
7 ; Craig Bruce device driver for the Switftlink/Turbo-232.
9 ; SwiftLink/Turbo-232 v0.90 device driver, by Craig Bruce, 14-Apr-1998.
11 ; This software is Public Domain. It is in Buddy assembler format.
13 ; This device driver uses the SwiftLink RS-232 Serial Cartridge, available from
14 ; Creative Micro Designs, Inc, and also supports the extensions of the Turbo232
15 ; Serial Cartridge. Both devices are based on the 6551 ACIA chip. It also
16 ; supports the "hacked" SwiftLink with a 1.8432 MHz crystal.
18 ; The code assumes that the kernal + I/O are in context. On the C128, call
19 ; it from Bank 15. On the C64, don't flip out the Kernal unless a suitable
20 ; NMI catcher is put into the RAM under then Kernal. For the SuperCPU, the
21 ; interrupt handling assumes that the 65816 is in 6502-emulation mode.
24 .include "zeropage.inc"
25 .include "ser-kernel.inc"
26 .include "ser-error.inc"
29 ; ------------------------------------------------------------------------
30 ; Header. Includes jump table
35 .byte $73, $65, $72 ; "ser"
36 .byte SER_API_VERSION ; Serial API version number
49 ;----------------------------------------------------------------------------
53 ACIA_DATA = ACIA+0 ; Data register
54 ACIA_STATUS = ACIA+1 ; Status register
55 ACIA_CMD = ACIA+2 ; Command register
56 ACIA_CTRL = ACIA+3 ; Control register
58 ;----------------------------------------------------------------------------
63 RecvHead: .res 1 ; Head of receive buffer
64 RecvTail: .res 1 ; Tail of receive buffer
65 RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
66 SendHead: .res 1 ; Head of send buffer
67 SendTail: .res 1 ; Tail of send buffer
68 SendFreeCnt: .res 1 ; Number of bytes in send buffer
70 Stopped: .res 1 ; Flow-stopped flag
73 RecvBuf: .res 256 ; Receive buffers: 256 bytes
74 SendBuf: .res 256 ; Send buffers: 256 bytes
76 Index: .res 1 ; I/O register index
80 Slot: .byte $02 ; Default to SSC in slot 2
84 ; Tables used to translate RS232 params into register values
85 BaudTable: ; bit7 = 1 means setting is invalid
86 .byte $FF ; SER_BAUD_45_5
87 .byte $01 ; SER_BAUD_50
88 .byte $02 ; SER_BAUD_75
89 .byte $03 ; SER_BAUD_110
90 .byte $04 ; SER_BAUD_134_5
91 .byte $05 ; SER_BAUD_150
92 .byte $06 ; SER_BAUD_300
93 .byte $07 ; SER_BAUD_600
94 .byte $08 ; SER_BAUD_1200
95 .byte $09 ; SER_BAUD_1800
96 .byte $0A ; SER_BAUD_2400
97 .byte $0B ; SER_BAUD_3600
98 .byte $0C ; SER_BAUD_4800
99 .byte $0D ; SER_BAUD_7200
100 .byte $0E ; SER_BAUD_9600
101 .byte $0F ; SER_BAUD_19200
102 .byte $FF ; SER_BAUD_38400
103 .byte $FF ; SER_BAUD_57600
104 .byte $FF ; SER_BAUD_115200
105 .byte $FF ; SER_BAUD_230400
107 .byte $60 ; SER_BITS_5
108 .byte $40 ; SER_BITS_6
109 .byte $20 ; SER_BITS_7
110 .byte $00 ; SER_BITS_8
112 .byte $00 ; SER_STOP_1
113 .byte $80 ; SER_STOP_2
115 .byte $00 ; SER_PAR_NONE
116 .byte $20 ; SER_PAR_ODD
117 .byte $60 ; SER_PAR_EVEN
118 .byte $A0 ; SER_PAR_MARK
119 .byte $E0 ; SER_PAR_SPACE
121 .byte $05 ; Pascal 1.0 ID byte
122 .byte $07 ; Pascal 1.0 ID byte
123 .byte $0B ; Pascal 1.1 generic signature byte
124 .byte $0C ; Device signature byte
129 .byte $31 ; Serial or parallel I/O card type 1
131 IdTableLen = * - IdValTable
135 ;----------------------------------------------------------------------------
136 ; INSTALL: Is called after the driver is loaded into memory. If possible,
137 ; check if the hardware is present. Must return an SER_ERR_xx code in a/x.
139 ; Since we don't have to manage the IRQ vector on the Apple II, this is
140 ; actually the same as:
142 ; UNINSTALL: Is called before the driver is removed from memory.
143 ; No return code required (the driver is removed from memory on return).
147 ; CLOSE: Close the port and disable interrupts. Called without parameters.
148 ; Must return an SER_ERR_xx code in a/x.
153 ldx Index ; Check for open port
156 ; Deactivate DTR and disable 6551 interrupts
160 ; Done, return an error code
163 stx Index ; Mark port as closed
166 ;----------------------------------------------------------------------------
167 ; OPEN: A pointer to a ser_params structure is passed in ptr1.
168 ; Must return an SER_ERR_xx code in a/x.
177 ; Check Pascal 1.1 Firmware Protocol ID bytes
186 ; Convert slot to I/O register index
194 ; Check if the handshake setting is valid
195 ldy #SER_PARAMS::HANDSHAKE ; Handshake
197 cmp #SER_HS_HW ; This is all we support
211 ; Set the value for the control register, which contains stop bits,
212 ; word length and the baud rate.
213 ldy #SER_PARAMS::BAUDRATE
214 lda (ptr1),y ; Baudrate index
216 lda BaudTable,y ; Get 6551 value
217 bmi InvBaud ; Branch if rate not supported
220 ldy #SER_PARAMS::DATABITS ; Databits
227 ldy #SER_PARAMS::STOPBITS ; Stopbits
232 ora #%00010000 ; Receiver clock source = baudrate
235 ; Set the value for the command register. We remember the base value
236 ; in RtsOff, since we will have to manipulate ACIA_CMD often.
237 ldy #SER_PARAMS::PARITY ; Parity
241 ora #%00000001 ; DTR active
243 ora #%00001000 ; Enable receive interrupts
247 stx Index ; Mark port as open
252 ; Device (hardware) not found
253 NoDevice:lda #<SER_ERR_NO_DEVICE
254 ldx #>SER_ERR_NO_DEVICE
258 InvParam:lda #<SER_ERR_INIT_FAILED
259 ldx #>SER_ERR_INIT_FAILED
262 ; Baud rate not available
263 InvBaud:lda #<SER_ERR_BAUD_UNAVAIL
264 ldx #>SER_ERR_BAUD_UNAVAIL
267 ;----------------------------------------------------------------------------
268 ; GET: Will fetch a character from the receive buffer and store it into the
269 ; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
274 ldy SendFreeCnt ; Send data if necessary
277 lda #$00 ; TryHard = false
280 ; Check for buffer empty
281 : lda RecvFreeCnt ; (25)
284 lda #<SER_ERR_NO_DATA
285 ldx #>SER_ERR_NO_DATA
288 ; Check for flow stopped & enough free: release flow control
299 ; Get byte from buffer
300 : ldy RecvHead ; (41)
306 txa ; Return code = 0
309 ;----------------------------------------------------------------------------
310 ; PUT: Output character in A.
311 ; Must return an SER_ERR_xx code in a/x.
321 lda #$00 ; TryHard = false
325 ; Put byte into send buffer & send
328 lda #<SER_ERR_OVERFLOW
329 ldx #>SER_ERR_OVERFLOW
336 lda #$FF ; TryHard = true
342 ;----------------------------------------------------------------------------
343 ; STATUS: Return the status in the variable pointed to by ptr1.
344 ; Must return an SER_ERR_xx code in a/x.
354 ;----------------------------------------------------------------------------
355 ; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
356 ; specific data in ptr1, and the ioctl code in A.
357 ; Must return an SER_ERR_xx code in a/x.
364 ; Check data to be [1..7]
374 : lda #<SER_ERR_INV_IOCTL
375 ldx #>SER_ERR_INV_IOCTL
378 ;----------------------------------------------------------------------------
379 ; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
380 ; registers are already saved, no parameters are passed, but the carry flag
381 ; is clear on entry. The routine must return with carry set if the interrupt
382 ; was handled, otherwise with carry clear.
385 ldx Index ; Check for open port
387 lda ACIA_STATUS,x ; Check ACIA status for receive interrupt
389 beq Done ; Jump if no ACIA interrupt
390 lda ACIA_DATA,x ; Get byte from ACIA
391 ldy RecvFreeCnt ; Check if we have free space left
392 beq Flow ; Jump if no space in receive buffer
393 ldy RecvTail ; Load buffer pointer
394 sta RecvBuf,y ; Store received byte in buffer
395 inc RecvTail ; Increment buffer pointer
396 dec RecvFreeCnt ; Decrement free space counter
397 ldy RecvFreeCnt ; Check for buffer space low
399 bcc Flow ; Assert flow control if buffer space low
400 rts ; Interrupt handled (carry already set)
402 ; Assert flow control if buffer space too low
406 sec ; Interrupt handled
409 ;----------------------------------------------------------------------------
410 ; Try to send a byte. Internal routine. A = TryHard
413 sta tmp1 ; Remember tryHard flag
414 Again: lda SendFreeCnt
418 ; Check for flow stopped
422 ; Check that ACIA is ready to send
426 bit tmp1 ; Keep trying if must try hard
430 ; Send byte and try again