2 ; Serial driver for the Telestrat integrated serial controller and the
3 ; Atmos with a serial add-on.
5 ; 2012-03-05, Stefan Haubenthal
6 ; 2013-07-15, Greg King
8 ; The driver is based on the cc65 rs232 module, which in turn is based on
9 ; Craig Bruce device driver for the Switftlink/Turbo-232.
11 ; SwiftLink/Turbo-232 v0.90 device driver, by Craig Bruce, 14-Apr-1998.
13 ; This software is Public Domain. It is in Buddy assembler format.
15 ; This device driver uses the SwiftLink RS-232 Serial Cartridge, available from
16 ; Creative Micro Designs, Inc, and also supports the extensions of the Turbo232
17 ; Serial Cartridge. Both devices are based on the 6551 ACIA chip. It also
18 ; supports the "hacked" SwiftLink with a 1.8432 MHz crystal.
20 ; The code assumes that the kernal + I/O are in context. On the C128, call
21 ; it from Bank 15. On the C64, don't flip out the Kernal unless a suitable
22 ; NMI catcher is put into the RAM under then Kernal. For the SuperCPU, the
23 ; interrupt handling assumes that the 65816 is in 6502-emulation mode.
26 .include "zeropage.inc"
27 .include "ser-kernel.inc"
28 .include "ser-error.inc"
31 ; ------------------------------------------------------------------------
32 ; Header. Includes jump table
37 .byte $73, $65, $72 ; "ser"
38 .byte SER_API_VERSION ; Serial API version number
54 ;----------------------------------------------------------------------------
59 RecvHead: .res 1 ; Head of receive buffer
60 RecvTail: .res 1 ; Tail of receive buffer
61 RecvFreeCnt: .res 1 ; Number of bytes in receive buffer
62 SendHead: .res 1 ; Head of send buffer
63 SendTail: .res 1 ; Tail of send buffer
64 SendFreeCnt: .res 1 ; Number of bytes in send buffer
66 Stopped: .res 1 ; Flow-stopped flag
69 RecvBuf: .res 256 ; Receive buffers: 256 bytes
70 SendBuf: .res 256 ; Send buffers: 256 bytes
72 Index: .res 1 ; I/O register index
76 ; Tables used to translate RS232 params into register values
77 BaudTable: ; bit7 = 1 means setting is invalid
78 .byte $FF ; SER_BAUD_45_5
79 .byte $01 ; SER_BAUD_50
80 .byte $02 ; SER_BAUD_75
81 .byte $03 ; SER_BAUD_110
82 .byte $04 ; SER_BAUD_134_5
83 .byte $05 ; SER_BAUD_150
84 .byte $06 ; SER_BAUD_300
85 .byte $07 ; SER_BAUD_600
86 .byte $08 ; SER_BAUD_1200
87 .byte $09 ; SER_BAUD_1800
88 .byte $0A ; SER_BAUD_2400
89 .byte $0B ; SER_BAUD_3600
90 .byte $0C ; SER_BAUD_4800
91 .byte $0D ; SER_BAUD_7200
92 .byte $0E ; SER_BAUD_9600
93 .byte $0F ; SER_BAUD_19200
94 .byte $FF ; SER_BAUD_38400
95 .byte $FF ; SER_BAUD_57600
96 .byte $FF ; SER_BAUD_115200
97 .byte $FF ; SER_BAUD_230400
99 .byte $60 ; SER_BITS_5
100 .byte $40 ; SER_BITS_6
101 .byte $20 ; SER_BITS_7
102 .byte $00 ; SER_BITS_8
104 .byte $00 ; SER_STOP_1
105 .byte $80 ; SER_STOP_2
107 .byte $00 ; SER_PAR_NONE
108 .byte $20 ; SER_PAR_ODD
109 .byte $60 ; SER_PAR_EVEN
110 .byte $A0 ; SER_PAR_MARK
111 .byte $E0 ; SER_PAR_SPACE
115 ;----------------------------------------------------------------------------
116 ; INSTALL: Is called after the driver is loaded into memory. If possible,
117 ; check if the hardware is present. Must return an SER_ERR_xx code in a/x.
119 ; Since we don't have to manage the IRQ vector on the Telestrat/Atmos, this is
120 ; actually the same as:
122 ; UNINSTALL: Is called before the driver is removed from memory.
123 ; No return code required (the driver is removed from memory on return).
127 ; CLOSE: Close the port and disable interrupts. Called without parameters.
128 ; Must return an SER_ERR_xx code in a/x.
133 ldx Index ; Check for open port
136 ; Deactivate DTR and disable 6551 interrupts
140 ; Done, return an error code
143 stx Index ; Mark port as closed
146 ;----------------------------------------------------------------------------
147 ; OPEN: A pointer to a ser_params structure is passed in ptr1.
148 ; Must return an SER_ERR_xx code in a/x.
151 ; Check if the handshake setting is valid
152 ldy #SER_PARAMS::HANDSHAKE ; Handshake
154 cmp #SER_HS_HW ; This is all we support
168 ; Set the value for the control register, which contains stop bits,
169 ; word length and the baud rate.
170 ldy #SER_PARAMS::BAUDRATE
171 lda (ptr1),y ; Baudrate index
173 lda BaudTable,y ; Get 6551 value
174 bmi InvBaud ; Branch if rate not supported
177 ldy #SER_PARAMS::DATABITS ; Databits
184 ldy #SER_PARAMS::STOPBITS ; Stopbits
189 ora #%00010000 ; Receiver clock source = baudrate
192 ; Set the value for the command register. We remember the base value
193 ; in RtsOff, since we will have to manipulate ACIA::CMD often.
194 ldy #SER_PARAMS::PARITY ; Parity
198 ora #%00000001 ; DTR active
200 ora #%00001000 ; Enable receive interrupts
204 stx Index ; Mark port as open
210 InvParam:lda #<SER_ERR_INIT_FAILED
211 ldx #>SER_ERR_INIT_FAILED
214 ; Baud rate not available
215 InvBaud:lda #<SER_ERR_BAUD_UNAVAIL
216 ldx #>SER_ERR_BAUD_UNAVAIL
219 ;----------------------------------------------------------------------------
220 ; GET: Will fetch a character from the receive buffer and store it into the
221 ; variable pointed to by ptr1. If no data is available, SER_ERR_NO_DATA is
225 ldy SendFreeCnt ; Send data if necessary
228 lda #$00 ; TryHard = false
231 ; Check for buffer empty
232 : lda RecvFreeCnt ; (25)
235 lda #<SER_ERR_NO_DATA
236 ldx #>SER_ERR_NO_DATA
239 ; Check for flow stopped & enough free: release flow control
250 ; Get byte from buffer
251 : ldy RecvHead ; (41)
257 txa ; Return code = 0
260 ;----------------------------------------------------------------------------
261 ; PUT: Output character in A.
262 ; Must return an SER_ERR_xx code in a/x.
270 lda #$00 ; TryHard = false
274 ; Put byte into send buffer & send
277 lda #<SER_ERR_OVERFLOW
278 ldx #>SER_ERR_OVERFLOW
285 lda #$FF ; TryHard = true
291 ;----------------------------------------------------------------------------
292 ; SER_STATUS: Return the status in the variable pointed to by ptr1.
293 ; Must return an SER_ERR_xx code in a/x.
302 ;----------------------------------------------------------------------------
303 ; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
304 ; specific data in ptr1, and the ioctl code in A.
305 ; Must return an SER_ERR_xx code in a/x.
308 lda #<SER_ERR_INV_IOCTL
309 ldx #>SER_ERR_INV_IOCTL
312 ;----------------------------------------------------------------------------
313 ; IRQ: Called from the builtin runtime IRQ handler as a subroutine. All
314 ; registers are already saved, no parameters are passed, but the carry flag
315 ; is clear on entry. The routine must return with carry set if the interrupt
316 ; was handled, otherwise with carry clear.
319 ldx Index ; Check for open port
321 lda ACIA::STATUS,x ; Check ACIA status for receive interrupt
323 beq Done ; Jump if no ACIA interrupt
324 lda ACIA::DATA,x ; Get byte from ACIA
325 ldy RecvFreeCnt ; Check if we have free space left
326 beq Flow ; Jump if no space in receive buffer
327 ldy RecvTail ; Load buffer pointer
328 sta RecvBuf,y ; Store received byte in buffer
329 inc RecvTail ; Increment buffer pointer
330 dec RecvFreeCnt ; Decrement free space counter
331 ldy RecvFreeCnt ; Check for buffer space low
333 bcc Flow ; Assert flow control if buffer space low
334 rts ; Interrupt handled (carry already set)
336 ; Assert flow control if buffer space too low
340 sec ; Interrupt handled
343 ;----------------------------------------------------------------------------
344 ; Try to send a byte. Internal routine. A = TryHard
347 sta tmp1 ; Remember tryHard flag
348 Again: lda SendFreeCnt
352 ; Check for flow stopped
356 ; Check that ACIA is ready to send
360 bit tmp1 ; Keep trying if must try hard
364 ; Send byte and try again