Code:
'****************************************************************
'* Name : UNTITLED.BAS *
'* Author : [Alan Paton] *
'* Notice : Copyright (c) 2009 *
'* : All Rights Reserved *
'* Date : 2/17/2009 *
'* Version : 1.0 *
'* Notes : *
'* http://www.interak.pwp.blueyonder.co.uk/PCtoASCII.htm *
'****************************************************************
@MyConfig = _HS_OSC & _LVP_OFF & _WDT_OFF & _CP_OFF
@MyConfig = MyConfig & _BODEN_OFF & _MCLRE_ON & _PWRTE_ON
@ __CONFIG MyConfig
;@ device INTRC_OSC_NOCLKOUT ;use internal oscillator
; DEFINE OSC 4
CMCON = 7
DEFINE OSC 20
PBIT VAR BYTE
D VAR BYTE[12]
SC VAR BYTE
CNT VAR BYTE
J VAR BYTE
CLK VAR PORTA.0
DAT VAR PORTA.1
CL VAR BYTE
SH VAR BYTE
AC VAR BYTE
LN VAR BYTE
LB VAR BYTE
'initialise
PAUSE 1000 ' wait for keyboard to start up
TRISB = 0
TrisA = 0
SH = 0
CNT = 0
CL = 0
GOTO SCAN
START:
IF SC=$12 OR SC = $59 THEN ' shift key up
SH = 0 ' reset shift
ENDIF
IF SC = $14 THEN ' control key up
CNT = 0 ' reset control flag
ENDIF
lb = 0 'clear last-byte flag
'Setup ports to read keyboard ******************
' ************ SCAN shifts serial scancode into SC *********
SCAN:
sc = 0 ' clear scan code
TrisA.1 = 1 ' set DAT to input
TrisA.0 = 1 ' set CLK to input
' Wait for clock transistion
LP1: ' make sure clock is high
IF CLK = 0 THEN
GOTO LP1
ENDIF
LP2:
IF CLK = 1 THEN ' clock idles high
GOTO LP2 ' wait for clock to go low
ENDIF
'clock now low - Start bit of scan code
FOR J = 0 TO 9 ' get scan code
LP3:
IF CLK = 0 THEN ' make sure clock is high
GOTO LP3
ENDIF
D(J) = DAT 'read data bit
NEXT J
' shift bits into variable SC
FOR J = 7 TO 0 STEP -1 ' D(8) & D(9) are parity & stop bits
SC = SC << 1 ' shift 1 place left
SC = SC + D(J) ' set bit 0 of SC LSB = 0 MSB = 7
NEXT J
TrisA.0 = 0 ' set CLK to output
CLK = 0 ' and hold it
IF LB = 2 THEN ' last byte of up - code - don't display
GOTO START
ENDIF
IF SC = $F0 THEN ' Check for key-up code
LB = 2 ' Set last byte flag
GOTO SCAN
ENDIF
IF SC = $12 OR SC = $59 THEN ' left and right shift keys
SH = $80 ' Set shift flag
GOTO SCAN
ENDIF
IF SC = $58 THEN ' Caps lock on
GOSUB CPLOCK
GOTO SCAN
ENDIF
IF SC = $E0 THEN ' Extended keys
GOTO SCAN ' Get next byte
ENDIF
IF SC = $14 THEN ' Left control key (& right . . $EO $14 )
CNT = 2 ' Set flag
GOTO SCAN
ENDIF
' and into SCAN CODE to ACSII conversion
' **************** CONVERT TO ASCII CODE ***************************
' scan code in SC
ASCII:
IF SC = $5A THEN 'is it CR ?
AC = $0D
GOTO ASOUT ' Yes send it
ENDIF
SC = SC + SH 'SH=$80 if shift key down (0 if not)
LN = $FF ' Set List No. to high value
' convert to ASCII (codes from 20H to 7FH)
LOOKDOWN SC,[$29,$96,$9E,$5D,$A5,$BD,$52,$C6,$C5,$BE,$D5,_
$41,$4E,$49,$4A,$45,$16,$1E,$26,$25,$2E,$36,$3D,$3E,$46,$CC,$4C,$C1,$55,_
$C9,$CA,$D2,$9C,$B2,$A1,$A3,$A4,$AB,$B4,$B3,$C3,$BB,$C2,$CB,$BA,$B1,$C4,_
$CD,$95,$AD,$9B,$AC,$BC,$AA,$9D,$A2,$B5,$9A,$54,$61,$5B,$B6,$CE,$A6,$1C,_
$32,$21,$23,$24,$2B,$34,$33,$43,$3B,$42,$4B,$3A,$31,$44,$4D,$15,$2D,$1B,_
$2C,$3C,$2A,$1D,$22,$35,$1A,$D4,$E1,$DB,$DD,$66],LN
IF LN = $FF THEN ' Scan code not found
GOTO NUMPAD ' Now check number pad
ENDIF
' Matching scan code has been found
IF CNT = 2 THEN 'Is control key pressed ?
AC = LN - $40 ' Get ASCII code
GOTO ASOUT ' Send it
ENDIF
' CAPS LOCK ON - check for the following conditions
IF LN>$40 AND LN<$5B THEN ' caps lock on & lower case selected
AC=LN
GOTO ASOUT
ENDIF
IF LN=$1B THEN ' caps lock on & (semi)colon selected
AC=$3A 'ASCII code for colon
GOTO ASOUT
ENDIF
GOTO AS2 'send out to computer keyboard port
' check number pad
NUMPAD:
LOOKDOWN SC,[$30,$31,$32,$33,$34,$35,$36,$37,$38,$39,$2A,$2D,$2B,$2E,$09,$1B],AC
GOTO ASOUT
AS2:
AC = LN + $20 ' Convert List No. to ASCII
ASOUT:
PortB.7 = 1 ' Strobe - normally high - pulse low
PAUSE 2
PortB = AC ' Send ASCII code to Port B
PAUSE 2 ' Bit 7 (strobe) is zero
pORTb.7 = 1
GOTO SCAN
END
' ********************* CAPS LOCK *********************************************
CPLOCK:
IF CL = 0 THEN ' Toggle caps lock
CL = 4 ' 4 IS BIT 2 0000 0100
ELSE
CL = 0
ENDIF
RETURN
Originally Posted by Joe S.
there is another bit not quite right. The PDF on the website definitely is OK because I printed it from the program listing.
Bookmarks