2 ; Serial driver for the Telestrat integrated serial controller and the
3 ; Atmos with a serial add-on.
5 ; Stefan Haubenthal, 2012-03-05
7 ; The driver is based on the cc65 rs232 module, which in turn is based on
8 ; Craig Bruce device driver for the Switftlink/Turbo-232.
10 ; SwiftLink/Turbo-232 v0.90 device driver, by Craig Bruce, 14-Apr-1998.
12 ; This software is Public Domain. It is in Buddy assembler format.
14 ; This device driver uses the SwiftLink RS-232 Serial Cartridge, available from
15 ; Creative Micro Designs, Inc, and also supports the extensions of the Turbo232
16 ; Serial Cartridge. Both devices are based on the 6551 ACIA chip. It also
17 ; supports the "hacked" SwiftLink with a 1.8432 MHz crystal.
19 ; The code assumes that the kernal + I/O are in context. On the C128, call
20 ; it from Bank 15. On the C64, don't flip out the Kernal unless a suitable
21 ; NMI catcher is put into the RAM under then Kernal. For the SuperCPU, the
22 ; interrupt handling assumes that the 65816 is in 6502-emulation mode.
25 .include "zeropage.inc"
26 .include "ser-kernel.inc"
27 .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 ; Tables used to translate RS232 params into register values
81 BaudTable: ; bit7 = 1 means setting is invalid
82 .byte $FF ; SER_BAUD_45_5
83 .byte $01 ; SER_BAUD_50
84 .byte $02 ; SER_BAUD_75
85 .byte $03 ; SER_BAUD_110
86 .byte $04 ; SER_BAUD_134_5
87 .byte $05 ; SER_BAUD_150
88 .byte $06 ; SER_BAUD_300
89 .byte $07 ; SER_BAUD_600
90 .byte $08 ; SER_BAUD_1200
91 .byte $09 ; SER_BAUD_1800
92 .byte $0A ; SER_BAUD_2400
93 .byte $0B ; SER_BAUD_3600
94 .byte $0C ; SER_BAUD_4800
95 .byte $0D ; SER_BAUD_7200
96 .byte $0E ; SER_BAUD_9600
97 .byte $0F ; SER_BAUD_19200
98 .byte $FF ; SER_BAUD_38400
99 .byte $FF ; SER_BAUD_57600
100 .byte $FF ; SER_BAUD_115200
101 .byte $FF ; SER_BAUD_230400
103 .byte $60 ; SER_BITS_5
104 .byte $40 ; SER_BITS_6
105 .byte $20 ; SER_BITS_7
106 .byte $00 ; SER_BITS_8
108 .byte $00 ; SER_STOP_1
109 .byte $80 ; SER_STOP_2
111 .byte $00 ; SER_PAR_NONE
112 .byte $20 ; SER_PAR_ODD
113 .byte $60 ; SER_PAR_EVEN
114 .byte $A0 ; SER_PAR_MARK
115 .byte $E0 ; SER_PAR_SPACE
119 ;----------------------------------------------------------------------------
120 ; INSTALL: Is called after the driver is loaded into memory. If possible,
121 ; check if the hardware is present. Must return an SER_ERR_xx code in a/x.
123 ; Since we don't have to manage the IRQ vector on the Telestrat/Atmos, this is
124 ; actually the same as:
126 ; UNINSTALL: Is called before the driver is removed from memory.
127 ; No return code required (the driver is removed from memory on return).
131 ; CLOSE: Close the port and disable interrupts. Called without parameters.
132 ; Must return an SER_ERR_xx code in a/x.
137 ldx Index ; Check for open port
140 ; Deactivate DTR and disable 6551 interrupts
144 ; Done, return an error code
147 stx Index ; Mark port as closed
150 ;----------------------------------------------------------------------------
151 ; OPEN: A pointer to a ser_params structure is passed in ptr1.
152 ; Must return an SER_ERR_xx code in a/x.
155 ; Check if the handshake setting is valid
156 ldy #SER_PARAMS::HANDSHAKE ; Handshake
158 cmp #SER_HS_HW ; This is all we support
172 ; Set the value for the control register, which contains stop bits,
173 ; word length and the baud rate.
174 ldy #SER_PARAMS::BAUDRATE
175 lda (ptr1),y ; Baudrate index
177 lda BaudTable,y ; Get 6551 value
178 bmi InvBaud ; Branch if rate not supported
181 ldy #SER_PARAMS::DATABITS ; Databits
188 ldy #SER_PARAMS::STOPBITS ; Stopbits
193 ora #%00010000 ; Receiver clock source = baudrate
196 ; Set the value for the command register. We remember the base value
197 ; in RtsOff, since we will have to manipulate ACIA_CMD often.
198 ldy #SER_PARAMS::PARITY ; Parity
202 ora #%00000001 ; DTR active
204 ora #%00001000 ; Enable receive interrupts
208 stx Index ; Mark port as open
214 InvParam:lda #<SER_ERR_INIT_FAILED
215 ldx #>SER_ERR_INIT_FAILED
218 ; Baud rate not available
219 InvBaud:lda #<SER_ERR_BAUD_UNAVAIL
220 ldx #>SER_ERR_BAUD_UNAVAIL
223 ;----------------------------------------------------------------------------
224 ; GET: Will fetch a character from the receive buffer and store it into the
225 ; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
229 ldy SendFreeCnt ; Send data if necessary
232 lda #$00 ; TryHard = false
235 ; Check for buffer empty
236 : lda RecvFreeCnt ; (25)
239 lda #<SER_ERR_NO_DATA
240 ldx #>SER_ERR_NO_DATA
243 ; Check for flow stopped & enough free: release flow control
254 ; Get byte from buffer
255 : ldy RecvHead ; (41)
261 txa ; Return code = 0
264 ;----------------------------------------------------------------------------
265 ; PUT: Output character in A.
266 ; Must return an SER_ERR_xx code in a/x.
274 lda #$00 ; TryHard = false
278 ; Put byte into send buffer & send
281 lda #<SER_ERR_OVERFLOW
282 ldx #>SER_ERR_OVERFLOW
289 lda #$FF ; TryHard = true
295 ;----------------------------------------------------------------------------
296 ; STATUS: Return the status in the variable pointed to by ptr1.
297 ; Must return an SER_ERR_xx code in a/x.
306 ;----------------------------------------------------------------------------
307 ; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
308 ; specific data in ptr1, and the ioctl code in A.
309 ; Must return an SER_ERR_xx code in a/x.
312 lda #<SER_ERR_INV_IOCTL
313 ldx #>SER_ERR_INV_IOCTL
316 ;----------------------------------------------------------------------------
317 ; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
318 ; registers are already saved, no parameters are passed, but the carry flag
319 ; is clear on entry. The routine must return with carry set if the interrupt
320 ; was handled, otherwise with carry clear.
323 ldx Index ; Check for open port
325 lda ACIA_STATUS,x ; Check ACIA status for receive interrupt
327 beq Done ; Jump if no ACIA interrupt
328 lda ACIA_DATA,x ; Get byte from ACIA
329 ldy RecvFreeCnt ; Check if we have free space left
330 beq Flow ; Jump if no space in receive buffer
331 ldy RecvTail ; Load buffer pointer
332 sta RecvBuf,y ; Store received byte in buffer
333 inc RecvTail ; Increment buffer pointer
334 dec RecvFreeCnt ; Decrement free space counter
335 ldy RecvFreeCnt ; Check for buffer space low
337 bcc Flow ; Assert flow control if buffer space low
338 rts ; Interrupt handled (carry already set)
340 ; Assert flow control if buffer space too low
344 sec ; Interrupt handled
347 ;----------------------------------------------------------------------------
348 ; Try to send a byte. Internal routine. A = TryHard
351 sta tmp1 ; Remember tryHard flag
352 Again: lda SendFreeCnt
356 ; Check for flow stopped
360 ; Check that ACIA is ready to send
364 bit tmp1 ; Keep trying if must try hard
368 ; Send byte and try again