Los fuentes 900x.
;
; PIC12C508 version of the "v5.3" serial data chip emulation.
; Written by the Old Crow (Scott Rider) on 6-JUN-97.
;
;
; Modified by Charles on 10-August 1998 for Model 7502
;
; 5 Wire Version.
;
; Modified by Charles on 6-July 1999 for Model 9002
;
; 4 Wire Version.
;
;
;
; Boots ALL Original Games and ALL Copied games.
;
;
; Revision History:
;
; P1.01v5 on 19-JAN-97 ;Uses v5.0 chip data
; P1.05 on 29-JAN-97 ;Uses ASCII version of v5.0 data
; P1.051 on 22-FEB-97 ;Fixed tiny, unimportant timing bug
; P1.052 on 06-JUN-97 ;Revised 5-wire version of '508 for 550x
; P1.053 on 08-JUN-97 ;Alternating 4MHz/4.45MHz delay on 5-wire
; P1.054 on 08-MAY-98 ;Fixed timing bug in 5-wire version
;
; This version uses Microchip assembler mnemonics and the
; Microchip MPASM assembler.
;
; Chip is connected in 5-wire fashion:
;
; _______ _______
; | \/ |
; Vdd --+ 1 << >> 8 +-- Vss
; | |
; GP5/OSC1 --+ 2 << >> 7 +-- GP0
; | |
; GP4/OSC2 --+ 3 >> 6 +-- GP1
; | |
; GP3/!MCLR --+ 4 << >> 5 +-- GP2/T0CKI
; | |
; +----------------+
;
;
; Note: change the "P509 EQU 0" to "P509 EQU 1" below to instruct
; the assembler to make the hex object code for a PIC12C509.
;
P509 EQU 0 ;Default assembles for a PIC12C508
IF P509
list p=12c509
include "p12c509.inc"
ELSE
list p=12c508
include "p12c508.inc"
ENDIF
radix dec
;
;
__FUSES _MCLRE_OFF & _CP_OFF & _WDT_OFF & _INT_OSC
cblock 0x07 ;Store variables above control registers
i ;Loop counters
j
k ;/
x ;Used by delay routine
y ;/
xmit ;Transmit data holding register
index ;Index register for table lookups
tstat ;Current TRIS setting
endc
org 0x00 ;Start of code space
movwf OSCCAL ;Set oscillator calibration reg.
goto start ;Jump into main code segment
;
; Support routines
;
; dly50 -- entry for 50ms delay
; dly_ms -- entry with number of ms in w (1 to 255)
;
dly50 movlw 50 ;Enter here for a 50ms delay
dly_ms movwf x ;/
dy_0 movlw 65 ;1ms loop count on 100x series
movwf y ;/
dy_1 btfsc GPIO,3 ;Check Input rb.3
bsf tstat,0 ;Set Output rb.0
btfss GPIO,3 ;Check Input rb.3
bcf tstat,0 ;Clear Output rb.0
movlw b'11111000' ;Set rb.5
btfss tstat,0 ;Check Timing Signal
movlw b'11011000' ;Clear rb.5
btfss tstat,1 ;Check Datagram
movlw b'11011000' ;Clear rb.5
movwf GPIO
movf tstat,W ;Read TRIS State
tris GPIO
decfsz y,F
goto dy_1
nop ;Another 6 Micro's
nop
nop
nop
nop
nop
dy_3 decfsz x,F ;# of 1ms delays
goto dy_0
retlw 3
;
; sendln -- send 4-byte line(s) with a 72ms marker at head of line.
; Enter with number of lines in w.
;
sendln movwf i ;Do this many lines
sl_0 movlw 72 ;Delay 72ms
call dly_ms
movlw 4 ;Do first half of line
movwf j ;/
sl_1 movf index,W ;Restore index
call lines ;Get a data byte..
movwf xmit ;..into xmit buffer
comf xmit,F ;Invert for sending
;
; Send a byte on rb.1. LSB first, 4ms/bit (250 bps) with one
; start bit and two stop bits per byte. Instead of setting and
; clearing the port bit, the port's direction is changed. The actual
; port register is set to zero, so that when the port bit is directed
; to be an output, it automatically goes low. Directing the port bit
; to be an input floats the I/O pin, and the external pullup creates
; the high. This allows open-collector operation of the port bits.
;
movlw 8 ;8 bit bytes
movwf k ;/
bsf tstat,1 ;Start bit on pin 6=1
movf tstat,W
tris GPIO
movlw 4 ;4ms bit-time
call dly_ms
sl_2 rrf xmit,F ;Get a bit..
btfsc STATUS,C ;High or low?
bsf tstat,1 ;Set pin 6 high via port direction control
btfss STATUS,C ;High or low?
bcf tstat,1 ;Set pin 6 low via port direction control
movf tstat,W
tris GPIO ;Set the port
movlw 4 ;Delay 4ms
call dly_ms
decfsz k,F ;Do all bits requested
goto sl_2
bcf tstat,1 ;Stop bits
movf tstat,W
tris GPIO
movlw 8 ;Two 4ms bit-times
call dly_ms
;
;
incf index,F ;Point to next
decfsz j,F
goto sl_1
decfsz i,F ;Do specified number of lines
goto sl_0
retlw 3
;
; Data block.
;
lines addwf PCL,F ;Get index into table
dt 'S','C','E','I' ;Japanese/NTSC
dt 'S','C','E','A' ;U.S./NTSC
dt 'S','C','E','E' ;European/PAL
;
; Main program loop.
;
org 0x0100
start movlw b'11000010' ;Set TMR0 prescaler = 1:8 (f_osc=4MHz)
option ;/
movlw b'11011111' ;Make all port bits inputs initially
movwf tstat
tris GPIO ;/
movlw b'11111000' ;Keep port bits low when outputs
movwf GPIO ;/
;
; Step 1 -- approx. 50ms after reset, I/O pin 6 goes low.
;
call dly50 ;Delay 50ms
bcf GPIO,0 ;Make sure PIN 7 is low
bcf GPIO,1 ;Make sure it's low
bcf tstat,1 ;Make rb.1 low via port direction
movf tstat,W
tris GPIO ;/
;
; Step 2 -- approx. 850ms later I/O pin 5 goes low.
;
step2 movlw 17 ;17 x 50ms = 850ms
movwf i ;/
s2_0 call dly50
decfsz i,F
goto s2_0 ;/
bcf GPIO,2 ;Make sure it's low
bcf tstat,2 ;Make rb.2 (and keep rb.1) low
movf tstat,W
tris GPIO ;/
;
; Step 3 -- wait approx. 314ms
;
step3 movlw 6 ;6 x 50ms = 300ms
movwf i ;/
s3_0 call dly50
decfsz i,F
goto s3_0 ;/
movlw 14 ;Final 14ms
call dly_ms
;
; Step 4 -- clock out all three datagrams on rb.1 ad infinitum.
;
step4 clrf index ;Do first line
call sendln
goto step4
;
; (Note: do NOT overwrite factory-programmed location 0x1FF !!)
;
; That's all, folks!
;
end
Si total, solo queremos 1 o 2... ![[+risas]](/images/smilies/nuevos/risa_ani3.gif "más risas")
) ![[sonrisa]](/images/smilies/nuevos/risa_ani1.gif "sonrisa")
. 