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"
30 ; ------------------------------------------------------------------------
31 ; Header. Includes jump table
34 module_header _a2e_ssc_ser
36 module_header _a2_ssc_ser
40 .byte $73, $65, $72 ; "ser"
41 .byte SER_API_VERSION ; Serial API version number
57 ;----------------------------------------------------------------------------
61 ACIA_DATA = ACIA+0 ; Data register
62 ACIA_STATUS = ACIA+1 ; Status register
63 ACIA_CMD = ACIA+2 ; Command register
64 ACIA_CTRL = ACIA+3 ; Control register
66 ;----------------------------------------------------------------------------
71 RecvHead: .res 1 ; Head of receive buffer
72 RecvTail: .res 1 ; Tail of receive buffer
73 RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
74 SendHead: .res 1 ; Head of send buffer
75 SendTail: .res 1 ; Tail of send buffer
76 SendFreeCnt: .res 1 ; Number of bytes in send buffer
78 Stopped: .res 1 ; Flow-stopped flag
81 RecvBuf: .res 256 ; Receive buffers: 256 bytes
82 SendBuf: .res 256 ; Send buffers: 256 bytes
84 Index: .res 1 ; I/O register index
88 Slot: .byte $02 ; Default to SSC in slot 2
92 ; Tables used to translate RS232 params into register values
93 BaudTable: ; bit7 = 1 means setting is invalid
94 .byte $FF ; SER_BAUD_45_5
95 .byte $01 ; SER_BAUD_50
96 .byte $02 ; SER_BAUD_75
97 .byte $03 ; SER_BAUD_110
98 .byte $04 ; SER_BAUD_134_5
99 .byte $05 ; SER_BAUD_150
100 .byte $06 ; SER_BAUD_300
101 .byte $07 ; SER_BAUD_600
102 .byte $08 ; SER_BAUD_1200
103 .byte $09 ; SER_BAUD_1800
104 .byte $0A ; SER_BAUD_2400
105 .byte $0B ; SER_BAUD_3600
106 .byte $0C ; SER_BAUD_4800
107 .byte $0D ; SER_BAUD_7200
108 .byte $0E ; SER_BAUD_9600
109 .byte $0F ; SER_BAUD_19200
110 .byte $FF ; SER_BAUD_38400
111 .byte $FF ; SER_BAUD_57600
112 .byte $FF ; SER_BAUD_115200
113 .byte $FF ; SER_BAUD_230400
115 .byte $60 ; SER_BITS_5
116 .byte $40 ; SER_BITS_6
117 .byte $20 ; SER_BITS_7
118 .byte $00 ; SER_BITS_8
120 .byte $00 ; SER_STOP_1
121 .byte $80 ; SER_STOP_2
123 .byte $00 ; SER_PAR_NONE
124 .byte $20 ; SER_PAR_ODD
125 .byte $60 ; SER_PAR_EVEN
126 .byte $A0 ; SER_PAR_MARK
127 .byte $E0 ; SER_PAR_SPACE
129 .byte $05 ; Pascal 1.0 ID byte
130 .byte $07 ; Pascal 1.0 ID byte
131 .byte $0B ; Pascal 1.1 generic signature byte
132 .byte $0C ; Device signature byte
137 .byte $31 ; Serial or parallel I/O card type 1
139 IdTableLen = * - IdValTable
143 ;----------------------------------------------------------------------------
144 ; INSTALL: Is called after the driver is loaded into memory. If possible,
145 ; check if the hardware is present. Must return an SER_ERR_xx code in a/x.
147 ; Since we don't have to manage the IRQ vector on the Apple II, this is
148 ; actually the same as:
150 ; UNINSTALL: Is called before the driver is removed from memory.
151 ; No return code required (the driver is removed from memory on return).
155 ; CLOSE: Close the port and disable interrupts. Called without parameters.
156 ; Must return an SER_ERR_xx code in a/x.
161 ldx Index ; Check for open port
164 ; Deactivate DTR and disable 6551 interrupts
168 ; Done, return an error code
171 stx Index ; Mark port as closed
174 ;----------------------------------------------------------------------------
175 ; OPEN: A pointer to a ser_params structure is passed in ptr1.
176 ; Must return an SER_ERR_xx code in a/x.
185 ; Check Pascal 1.1 Firmware Protocol ID bytes
194 ; Convert slot to I/O register index
202 ; Check if the handshake setting is valid
203 ldy #SER_PARAMS::HANDSHAKE ; Handshake
205 cmp #SER_HS_HW ; This is all we support
219 ; Set the value for the control register, which contains stop bits,
220 ; word length and the baud rate.
221 ldy #SER_PARAMS::BAUDRATE
222 lda (ptr1),y ; Baudrate index
224 lda BaudTable,y ; Get 6551 value
225 bmi InvBaud ; Branch if rate not supported
228 ldy #SER_PARAMS::DATABITS ; Databits
235 ldy #SER_PARAMS::STOPBITS ; Stopbits
240 ora #%00010000 ; Receiver clock source = baudrate
243 ; Set the value for the command register. We remember the base value
244 ; in RtsOff, since we will have to manipulate ACIA_CMD often.
245 ldy #SER_PARAMS::PARITY ; Parity
249 ora #%00000001 ; DTR active
251 ora #%00001000 ; Enable receive interrupts
255 stx Index ; Mark port as open
260 ; Device (hardware) not found
261 NoDevice:lda #<SER_ERR_NO_DEVICE
262 ldx #>SER_ERR_NO_DEVICE
266 InvParam:lda #<SER_ERR_INIT_FAILED
267 ldx #>SER_ERR_INIT_FAILED
270 ; Baud rate not available
271 InvBaud:lda #<SER_ERR_BAUD_UNAVAIL
272 ldx #>SER_ERR_BAUD_UNAVAIL
275 ;----------------------------------------------------------------------------
276 ; GET: Will fetch a character from the receive buffer and store it into the
277 ; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
282 ldy SendFreeCnt ; Send data if necessary
285 lda #$00 ; TryHard = false
288 ; Check for buffer empty
289 : lda RecvFreeCnt ; (25)
292 lda #<SER_ERR_NO_DATA
293 ldx #>SER_ERR_NO_DATA
296 ; Check for flow stopped & enough free: release flow control
307 ; Get byte from buffer
308 : ldy RecvHead ; (41)
314 txa ; Return code = 0
317 ;----------------------------------------------------------------------------
318 ; PUT: Output character in A.
319 ; Must return an SER_ERR_xx code in a/x.
329 lda #$00 ; TryHard = false
333 ; Put byte into send buffer & send
336 lda #<SER_ERR_OVERFLOW
337 ldx #>SER_ERR_OVERFLOW
344 lda #$FF ; TryHard = true
350 ;----------------------------------------------------------------------------
351 ; STATUS: Return the status in the variable pointed to by ptr1.
352 ; Must return an SER_ERR_xx code in a/x.
362 ;----------------------------------------------------------------------------
363 ; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
364 ; specific data in ptr1, and the ioctl code in A.
365 ; Must return an SER_ERR_xx code in a/x.
368 ; Check data msb and code to be 0
372 ; Check data lsb to be [1..7]
382 : lda #<SER_ERR_INV_IOCTL
383 ldx #>SER_ERR_INV_IOCTL
386 ;----------------------------------------------------------------------------
387 ; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
388 ; registers are already saved, no parameters are passed, but the carry flag
389 ; is clear on entry. The routine must return with carry set if the interrupt
390 ; was handled, otherwise with carry clear.
393 ldx Index ; Check for open port
395 lda ACIA_STATUS,x ; Check ACIA status for receive interrupt
397 beq Done ; Jump if no ACIA interrupt
398 lda ACIA_DATA,x ; Get byte from ACIA
399 ldy RecvFreeCnt ; Check if we have free space left
400 beq Flow ; Jump if no space in receive buffer
401 ldy RecvTail ; Load buffer pointer
402 sta RecvBuf,y ; Store received byte in buffer
403 inc RecvTail ; Increment buffer pointer
404 dec RecvFreeCnt ; Decrement free space counter
405 ldy RecvFreeCnt ; Check for buffer space low
407 bcc Flow ; Assert flow control if buffer space low
408 rts ; Interrupt handled (carry already set)
410 ; Assert flow control if buffer space too low
414 sec ; Interrupt handled
417 ;----------------------------------------------------------------------------
418 ; Try to send a byte. Internal routine. A = TryHard
421 sta tmp1 ; Remember tryHard flag
422 Again: lda SendFreeCnt
426 ; Check for flow stopped
430 ; Check that ACIA is ready to send
434 bit tmp1 ; Keep trying if must try hard
438 ; Send byte and try again