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
52 ;----------------------------------------------------------------------------
56 ACIA_DATA = ACIA+0 ; Data register
57 ACIA_STATUS = ACIA+1 ; Status register
58 ACIA_CMD = ACIA+2 ; Command register
59 ACIA_CTRL = ACIA+3 ; Control register
61 ;----------------------------------------------------------------------------
66 RecvHead: .res 1 ; Head of receive buffer
67 RecvTail: .res 1 ; Tail of receive buffer
68 RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
69 SendHead: .res 1 ; Head of send buffer
70 SendTail: .res 1 ; Tail of send buffer
71 SendFreeCnt: .res 1 ; Number of bytes in send buffer
73 Stopped: .res 1 ; Flow-stopped flag
76 RecvBuf: .res 256 ; Receive buffers: 256 bytes
77 SendBuf: .res 256 ; Send buffers: 256 bytes
79 Index: .res 1 ; I/O register index
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
122 ;----------------------------------------------------------------------------
123 ; INSTALL: Is called after the driver is loaded into memory. If possible,
124 ; check if the hardware is present. Must return an SER_ERR_xx code in a/x.
126 ; Since we don't have to manage the IRQ vector on the Telestrat/Atmos, this is
127 ; actually the same as:
129 ; UNINSTALL: Is called before the driver is removed from memory.
130 ; No return code required (the driver is removed from memory on return).
134 ; CLOSE: Close the port and disable interrupts. Called without parameters.
135 ; Must return an SER_ERR_xx code in a/x.
140 ldx Index ; Check for open port
143 ; Deactivate DTR and disable 6551 interrupts
147 ; Done, return an error code
150 stx Index ; Mark port as closed
153 ;----------------------------------------------------------------------------
154 ; OPEN: A pointer to a ser_params structure is passed in ptr1.
155 ; Must return an SER_ERR_xx code in a/x.
158 ; Check if the handshake setting is valid
159 ldy #SER_PARAMS::HANDSHAKE ; Handshake
161 cmp #SER_HS_HW ; This is all we support
175 ; Set the value for the control register, which contains stop bits,
176 ; word length and the baud rate.
177 ldy #SER_PARAMS::BAUDRATE
178 lda (ptr1),y ; Baudrate index
180 lda BaudTable,y ; Get 6551 value
181 bmi InvBaud ; Branch if rate not supported
184 ldy #SER_PARAMS::DATABITS ; Databits
191 ldy #SER_PARAMS::STOPBITS ; Stopbits
196 ora #%00010000 ; Receiver clock source = baudrate
199 ; Set the value for the command register. We remember the base value
200 ; in RtsOff, since we will have to manipulate ACIA_CMD often.
201 ldy #SER_PARAMS::PARITY ; Parity
205 ora #%00000001 ; DTR active
207 ora #%00001000 ; Enable receive interrupts
211 stx Index ; Mark port as open
217 InvParam:lda #<SER_ERR_INIT_FAILED
218 ldx #>SER_ERR_INIT_FAILED
221 ; Baud rate not available
222 InvBaud:lda #<SER_ERR_BAUD_UNAVAIL
223 ldx #>SER_ERR_BAUD_UNAVAIL
226 ;----------------------------------------------------------------------------
227 ; GET: Will fetch a character from the receive buffer and store it into the
228 ; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
232 ldy SendFreeCnt ; Send data if necessary
235 lda #$00 ; TryHard = false
238 ; Check for buffer empty
239 : lda RecvFreeCnt ; (25)
242 lda #<SER_ERR_NO_DATA
243 ldx #>SER_ERR_NO_DATA
246 ; Check for flow stopped & enough free: release flow control
257 ; Get byte from buffer
258 : ldy RecvHead ; (41)
264 txa ; Return code = 0
267 ;----------------------------------------------------------------------------
268 ; PUT: Output character in A.
269 ; Must return an SER_ERR_xx code in a/x.
277 lda #$00 ; TryHard = false
281 ; Put byte into send buffer & send
284 lda #<SER_ERR_OVERFLOW
285 ldx #>SER_ERR_OVERFLOW
292 lda #$FF ; TryHard = true
298 ;----------------------------------------------------------------------------
299 ; STATUS: Return the status in the variable pointed to by ptr1.
300 ; Must return an SER_ERR_xx code in a/x.
309 ;----------------------------------------------------------------------------
310 ; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
311 ; specific data in ptr1, and the ioctl code in A.
312 ; Must return an SER_ERR_xx code in a/x.
315 lda #<SER_ERR_INV_IOCTL
316 ldx #>SER_ERR_INV_IOCTL
319 ;----------------------------------------------------------------------------
320 ; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
321 ; registers are already saved, no parameters are passed, but the carry flag
322 ; is clear on entry. The routine must return with carry set if the interrupt
323 ; was handled, otherwise with carry clear.
326 ldx Index ; Check for open port
328 lda ACIA_STATUS,x ; Check ACIA status for receive interrupt
330 beq Done ; Jump if no ACIA interrupt
331 lda ACIA_DATA,x ; Get byte from ACIA
332 ldy RecvFreeCnt ; Check if we have free space left
333 beq Flow ; Jump if no space in receive buffer
334 ldy RecvTail ; Load buffer pointer
335 sta RecvBuf,y ; Store received byte in buffer
336 inc RecvTail ; Increment buffer pointer
337 dec RecvFreeCnt ; Decrement free space counter
338 ldy RecvFreeCnt ; Check for buffer space low
340 bcc Flow ; Assert flow control if buffer space low
341 rts ; Interrupt handled (carry already set)
343 ; Assert flow control if buffer space too low
347 sec ; Interrupt handled
350 ;----------------------------------------------------------------------------
351 ; Try to send a byte. Internal routine. A = TryHard
354 sta tmp1 ; Remember tryHard flag
355 Again: lda SendFreeCnt
359 ; Check for flow stopped
363 ; Check that ACIA is ready to send
367 bit tmp1 ; Keep trying if must try hard
371 ; Send byte and try again