;; The following code is written and is copyrighted by
;; Groepaz/Hitmen
;; Small changes by Adam Dunkels (renamed ss232 -> rs232)
;----------------------------------------------------------------------------------------------
; silver surfer polling mode driver for cc65
; - work from here to create a full featured driver with interupts.
; gpz fixed 20020828: fatal bug fixed in _rs232_params
;----------------------------------------------------------------------------------------------
rs16550base = $de08
fifo_rxd = rs16550base+$00 ;8 (r)
fifo_txd = rs16550base+$00 ;8 (w)
fifo_dll = rs16550base+$00 ;8 (r/w)
fifo_dlm = rs16550base+$01 ;9 (r/w)
fifo_ier = rs16550base+$01 ;9
fifo_fcr = rs16550base+$02 ;a (w)
fifo_iir = rs16550base+$02 ;a (r)
fifo_lcr = rs16550base+$03 ;b
fifo_mcr = rs16550base+$04 ;c
fifo_lsr = rs16550base+$05 ;d
fifo_msr = rs16550base+$06 ;e (r)
fifo_scratch = rs16550base+$07 ;f (r/w)
.export _rs232_init
.export _rs232_done
.export _rs232_params
.export _rs232_put
.export _rs232_get
.importzp ptr1, ptr2
.import popa, popax
;----------------------------------------------------------------------------------------------
; Error codes. Beware: The codes must match the codes in the C header file
ErrNotInitialized = $01
ErrBaudTooFast = $02
ErrBaudNotAvail = $03
ErrNoData = $04
ErrOverflow = $05
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_init (char hacked);
;/* Initialize the serial port, install the interrupt handler. The parameter
; * has no effect for now and should be set to 0.
; */
;----------------------------------------------------------------------------------------------
.code
_rs232_init:
; enable ssurfer-port
lda $de01
ora #$01
sta $de01
; disable nmi's from ssurfer
lda #%00000000
sta fifo_ier
; activate dtr
lda #%00000001
sta fifo_mcr
lda #$00 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_done (void);
;/* Close the port, deinstall the interrupt hander. You MUST call this function
; * before terminating the program, otherwise the machine may crash later. If
; * in doubt, install an exit handler using atexit(). The function will do
; * nothing, if it was already called.
; */
;----------------------------------------------------------------------------------------------
_rs232_done:
; disable nmi's from ssurfer
lda #%00000000
sta fifo_ier
; deactivate dtr
sta fifo_mcr
; disable ssurfer-port
lda $de01
and #$fe
sta $de01
lda #$00 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_params (unsigned char params, unsigned char parity);
;/* Set the port parameters. Use a combination of the #defined values above. */
;----------------------------------------------------------------------------------------------
.data
_rs232_baudrates:
.word (7372800 / ( 50 * 16))
.word (7372800 / ( 110 * 16))
.word (7372800 / ( 269 * 8))
.word (7372800 / ( 300 * 16))
.word (7372800 / ( 600 * 16))
.word (7372800 / ( 1200 * 16))
.word (7372800 / ( 2400 * 16))
.word (7372800 / ( 4800 * 16))
.word (7372800 / ( 9600 * 16))
.word (7372800 / ( 19200 * 16))
.word (7372800 / ( 38400 * 16))
.word (7372800 / ( 57600 * 16))
.word (7372800 / ( 115200 * 16))
.word (7372800 / ( 230400 * 16))
.bss
_rs232_tmp1:
.res 1
.code
_rs232_params:
sta _rs232_tmp1 ; save parity
; reset fifo
lda #%10000111
sta fifo_fcr
; that delay thing really needed ?!
; (original datasheet mentions a delay here)
; ldy #$00
; dey
; bny *-1
; set dlab
lda #%10000011 ; we assmume 8n1
sta fifo_lcr
jsr popa
tay ; save param
; set baudrate
clc
lsr a
lsr a
lsr a
lsr a
asl a
tax
lda _rs232_baudrates,x
sta fifo_dll
lda _rs232_baudrates+1,x
sta fifo_dlm
tya ; param
and #$0f
ora _rs232_tmp1 ; parity
; reset dlab
sta fifo_lcr
lda #$00 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
; check if byte available, returns AKKU=0 if none
ss_getlsr:
lda fifo_lsr
and #$01
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_get (char* b);
;/* Get a character from the serial port. If no characters are available, the
; * function will return RS_ERR_NO_DATA, so this is not a fatal error.
; */
;----------------------------------------------------------------------------------------------
; get byte (non blocking, returns byte in A or CARRY=1 - error)
_rs232_get:
sta ptr1
stx ptr1+1
jsr ss_getlsr ; check if byte available
; bne sk32 ; yes
bne sk33 ; yes
; activate rts
lda #%00000011
sta fifo_mcr
sk32:
; deactivate rts
; lda #%00000001
; sta fifo_mcr
jsr ss_getlsr ; check if byte available
bne sk33 ; yes
; deactivate rts
lda #%00000001
sta fifo_mcr
lda #ErrNoData ; no data
ldx #0
rts
sk33:
; deactivate rts
lda #%00000001
sta fifo_mcr
; get byte
ldy #$00
lda fifo_rxd
sta (ptr1),y
lda #0 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_put (char b);
;/* Send a character via the serial port. There is a transmit buffer, but
; * transmitting is not done via interrupt. The function returns
; * RS_ERR_OVERFLOW if there is no space left in the transmit buffer.
; */
;----------------------------------------------------------------------------------------------
_rs232_put:
tax
; transmit buf ready?
lda fifo_lsr
and #%00100000
bne @sk1
@sk2:
lda #ErrOverflow ; overflow
ldx #$00
rts
@sk1:
; reciever ready?
lda fifo_msr
and #%00010000
beq @sk2
stx fifo_txd
lda #$00 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_pause (void);
;/* Assert flow control and disable interrupts. */
;----------------------------------------------------------------------------------------------
_rs232_pause:
; activate rts
lda #%00000011
sta fifo_mcr
lda #$00 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_unpause (void);
;/* Re-enable interrupts and release flow control */
;----------------------------------------------------------------------------------------------
_rs232_unpause:
; deactivate rts
lda #%00000001
sta fifo_mcr
lda #$00 ; ok
tax
rts
;----------------------------------------------------------------------------------------------
;unsigned char __fastcall__ rs232_status (unsigned char* status,
; unsigned char* errors);
;/* Return the serial port status. */
;----------------------------------------------------------------------------------------------
_rs232_status:
sta ptr2
stx ptr2+1
jsr popax
sta ptr1
stx ptr1+1
ldy #$00
; Get status
lda fifo_iir
and #%00000001
sta _rs232_tmp1
lda fifo_msr
lsr a
and #%01010000
ora _rs232_tmp1
sta _rs232_tmp1
lda fifo_lsr
and #%00101110
ora _rs232_tmp1
sta (ptr1),y
; Get errors
lda #$00 ; ok
sta (ptr2),y
lda #$00 ; ok
tax
rts