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"
28 ; ------------------------------------------------------------------------
29 ; Header. Includes jump table
34 .byte $73, $65, $72 ; "ser"
35 .byte SER_API_VERSION ; Serial API version number
48 ;----------------------------------------------------------------------------
52 ACIA_DATA = ACIA+0 ; Data register
53 ACIA_STATUS = ACIA+1 ; Status register
54 ACIA_CMD = ACIA+2 ; Command register
55 ACIA_CTRL = ACIA+3 ; Control register
57 ;----------------------------------------------------------------------------
62 RecvHead: .res 1 ; Head of receive buffer
63 RecvTail: .res 1 ; Tail of receive buffer
64 RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
65 SendHead: .res 1 ; Head of send buffer
66 SendTail: .res 1 ; Tail of send buffer
67 SendFreeCnt: .res 1 ; Number of bytes in send buffer
69 Stopped: .res 1 ; Flow-stopped flag
72 RecvBuf: .res 256 ; Receive buffers: 256 bytes
73 SendBuf: .res 256 ; Send buffers: 256 bytes
75 Index: .res 1 ; I/O register index
79 Slot: .byte $02 ; Default to SSC in slot 2
83 ; Tables used to translate RS232 params into register values
84 BaudTable: ; bit7 = 1 means setting is invalid
85 .byte $FF ; SER_BAUD_45_5
86 .byte $01 ; SER_BAUD_50
87 .byte $02 ; SER_BAUD_75
88 .byte $03 ; SER_BAUD_110
89 .byte $04 ; SER_BAUD_134_5
90 .byte $05 ; SER_BAUD_150
91 .byte $06 ; SER_BAUD_300
92 .byte $07 ; SER_BAUD_600
93 .byte $08 ; SER_BAUD_1200
94 .byte $09 ; SER_BAUD_1800
95 .byte $0A ; SER_BAUD_2400
96 .byte $0B ; SER_BAUD_3600
97 .byte $0C ; SER_BAUD_4800
98 .byte $0D ; SER_BAUD_7200
99 .byte $0E ; SER_BAUD_9600
100 .byte $0F ; SER_BAUD_19200
101 .byte $FF ; SER_BAUD_38400
102 .byte $FF ; SER_BAUD_57600
103 .byte $FF ; SER_BAUD_115200
104 .byte $FF ; SER_BAUD_230400
106 .byte $60 ; SER_BITS_5
107 .byte $40 ; SER_BITS_6
108 .byte $20 ; SER_BITS_7
109 .byte $00 ; SER_BITS_8
111 .byte $00 ; SER_STOP_1
112 .byte $80 ; SER_STOP_2
114 .byte $00 ; SER_PAR_NONE
115 .byte $20 ; SER_PAR_ODD
116 .byte $60 ; SER_PAR_EVEN
117 .byte $A0 ; SER_PAR_MARK
118 .byte $E0 ; SER_PAR_SPACE
120 .byte $05 ; Pascal 1.0 ID byte
121 .byte $07 ; Pascal 1.0 ID byte
122 .byte $0B ; Pascal 1.1 generic signature byte
123 .byte $0C ; Device signature byte
128 .byte $31 ; Serial or parallel I/O card type 1
130 IdTableLen = * - IdValTable
134 ;----------------------------------------------------------------------------
135 ; INSTALL: Is called after the driver is loaded into memory. If possible,
136 ; check if the hardware is present. Must return an SER_ERR_xx code in a/x.
138 ; Since we don't have to manage the IRQ vector on the Apple II, this is
139 ; actually the same as:
141 ; UNINSTALL: Is called before the driver is removed from memory.
142 ; No return code required (the driver is removed from memory on return).
146 ; CLOSE: Close the port and disable interrupts. Called without parameters.
147 ; Must return an SER_ERR_xx code in a/x.
152 ldx Index ; Check for open port
155 ; Deactivate DTR and disable 6551 interrupts
159 ; Done, return an error code
162 stx Index ; Mark port as closed
165 ;----------------------------------------------------------------------------
166 ; OPEN: A pointer to a ser_params structure is passed in ptr1.
167 ; Must return an SER_ERR_xx code in a/x.
176 ; Check Pascal 1.1 Firmware Protocol ID bytes
185 ; Convert slot to I/O register index
193 ; Check if the handshake setting is valid
194 ldy #SER_PARAMS::HANDSHAKE ; Handshake
196 cmp #SER_HS_HW ; This is all we support
210 ; Set the value for the control register, which contains stop bits,
211 ; word length and the baud rate.
212 ldy #SER_PARAMS::BAUDRATE
213 lda (ptr1),y ; Baudrate index
215 lda BaudTable,y ; Get 6551 value
216 bmi InvBaud ; Branch if rate not supported
219 ldy #SER_PARAMS::DATABITS ; Databits
226 ldy #SER_PARAMS::STOPBITS ; Stopbits
231 ora #%00010000 ; Receiver clock source = baudrate
234 ; Set the value for the command register. We remember the base value
235 ; in RtsOff, since we will have to manipulate ACIA_CMD often.
236 ldy #SER_PARAMS::PARITY ; Parity
240 ora #%00000001 ; DTR active
242 ora #%00001000 ; Enable receive interrupts
246 stx Index ; Mark port as open
251 ; Device (hardware) not found
252 NoDevice:lda #<SER_ERR_NO_DEVICE
253 ldx #>SER_ERR_NO_DEVICE
257 InvParam:lda #<SER_ERR_INIT_FAILED
258 ldx #>SER_ERR_INIT_FAILED
261 ; Baud rate not available
262 InvBaud:lda #<SER_ERR_BAUD_UNAVAIL
263 ldx #>SER_ERR_BAUD_UNAVAIL
266 ;----------------------------------------------------------------------------
267 ; GET: Will fetch a character from the receive buffer and store it into the
268 ; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
273 ldy SendFreeCnt ; Send data if necessary
276 lda #$00 ; TryHard = false
279 ; Check for buffer empty
280 : lda RecvFreeCnt ; (25)
283 lda #<SER_ERR_NO_DATA
284 ldx #>SER_ERR_NO_DATA
287 ; Check for flow stopped & enough free: release flow control
298 ; Get byte from buffer
299 : ldy RecvHead ; (41)
305 txa ; Return code = 0
308 ;----------------------------------------------------------------------------
309 ; PUT: Output character in A.
310 ; Must return an SER_ERR_xx code in a/x.
320 lda #$00 ; TryHard = false
324 ; Put byte into send buffer & send
327 lda #<SER_ERR_OVERFLOW
328 ldx #>SER_ERR_OVERFLOW
335 lda #$FF ; TryHard = true
341 ;----------------------------------------------------------------------------
342 ; STATUS: Return the status in the variable pointed to by ptr1.
343 ; Must return an SER_ERR_xx code in a/x.
353 ;----------------------------------------------------------------------------
354 ; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
355 ; specific data in ptr1, and the ioctl code in A.
356 ; Must return an SER_ERR_xx code in a/x.
363 ; Check data to be [1..7]
373 : lda #<SER_ERR_INV_IOCTL
374 ldx #>SER_ERR_INV_IOCTL
377 ;----------------------------------------------------------------------------
378 ; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
379 ; registers are already saved, no parameters are passed, but the carry flag
380 ; is clear on entry. The routine must return with carry set if the interrupt
381 ; was handled, otherwise with carry clear.
384 ldx Index ; Check for open port
386 lda ACIA_STATUS,x ; Check ACIA status for receive interrupt
388 beq Done ; Jump if no ACIA interrupt
389 lda ACIA_DATA,x ; Get byte from ACIA
390 ldy RecvFreeCnt ; Check if we have free space left
391 beq Flow ; Jump if no space in receive buffer
392 ldy RecvTail ; Load buffer pointer
393 sta RecvBuf,y ; Store received byte in buffer
394 inc RecvTail ; Increment buffer pointer
395 dec RecvFreeCnt ; Decrement free space counter
396 ldy RecvFreeCnt ; Check for buffer space low
398 bcc Flow ; Assert flow control if buffer space low
399 rts ; Interrupt handled (carry already set)
401 ; Assert flow control if buffer space too low
405 sec ; Interrupt handled
408 ;----------------------------------------------------------------------------
409 ; Try to send a byte. Internal routine. A = TryHard
412 sta tmp1 ; Remember tryHard flag
413 Again: lda SendFreeCnt
417 ; Check for flow stopped
421 ; Check that ACIA is ready to send
425 bit tmp1 ; Keep trying if must try hard
429 ; Send byte and try again