MEL PICBASIC Forum - Include File Submission

  • KeyboardNumberInput.bas

    by
    Charles Linquis
    Published on - 20th September 2011 07:47
    For those who need to have a means to input numerical user responses into their program from a serial terminal.
    Most of the commonly-used methods (like HSERIN [DEC numdata] work, but provide no user feedback as to what they are typing. It also doesn't allow for backspacing. This include file provides both.

    As an added bonus, the file lets you input negative numbers by typing a "-" before the number. And, because people who are used to occasionally putting a "-" before their entry may also put a "+", the file will accept this also.

    This routine will work with most serial terminal programs, like HYPERTERM and Bray's TERMINAL. No fancy emulation modes (VT-XX) need to be selected.

    The INCLUDE has several defaults that can be overridden by changing the values of certain variables before the INCLUDE is called via a GOSUB. These defaults include the maximum number of characters (MAXCHAR), whether or not "-" and "+" will be allowed before the number entry (ALLLOWSIGN), and the timeout - how long the routine will wait with no input before returning.

    If the MAXCHAR limit is reached, the value is returned as if an <ENTER> had been pressed. Of course, an <ENTER> can be pressed at any time. 5 is the default.

    If ALLOWSIGN = 1, then a "+" or "-" will be allowed - BUT ONLY IN THE LEFTMOST POSITION. A "+" is displayed, but "thrown away" later. A "-" on the other hand, will return the twos compliment of the number.

    Pressing <ESC> will return the value of zero and set bit 2 of the variable KERROR. Likewise, entering nothing will cause a timeout and will set KERROR bit 1 and return a value of zero. Entering a negative number that is too large will set KERROR bit 0.

    Kerror bit 7 will be set if the returned value is negative.

    The returned value is KRETURNED.

    To invoke the utility :
    GOSUB GETNUM

    This routine is written for hardware serial ports. Although software ports (SERIN2) CAN be used, I discourage this horrible practice whenever I can.

    USAGE:

    <Set up serial port>

    INCLUDE "KBNumberInput.bas"

    <Change defaults, if desired>

    ...
    ...
    ...

    Hserout [CR,LF,"Give me the number "]
    Gosub GetNum

    IF !Kerror then
    HSEROUT [CR,LF,"The number you typed in was ",#KResult]
    else
    if Kerror.7 then
    HSEROUT [CR,LF,"The NEGATIVE number you typed in was ",SDEC Keyresult]
    else
    <Process errors here>
    endif
    endif


    Code:
    ;-----------------------------------------------------------------------------------------
; Numeric Input Routine by Charles Linquist
; Set MaxNum to maximum number of digits you will take (default = 5)
; Set KInputTimeout to the number of secs you will wait before giving up.
; If you will accept a sign ("+" or "-") then set AllowSign to 1 in your
; program it will over-ride these values
; 
; KRESULT is , well, the result.
;-----------------------------------------------------------------------------------------

        Keyin var byte
        Maxnum var byte
        YY var word
        POSN var byte
        AllowSign var bit
        Kerror var Byte
        KInputString var byte [10]
        KResult Var word
        KInputTimeout var Word
        XN var byte

        BS CON 8
        ESC cON 27
        LF con 10
        SP con 32
        CR con 13

        MaxNum = 5     ; max number of chars
        KInputTimeout = 10000 ; 10 sec
        AllowSign = 0 
        
        goto OverKInput 

GetNum:
       
        KResult = 0
        Kerror = 0
        YY = 1
        POSN=0
        
        ArrayWrite KInputString,[Rep $FF\8]  ; Fill with $FF
 
GetMoreN:              
        HSERIN KInputTimeout,DeadAtKeyboard,[Keyin]
            IF Keyin = ESC THEN Escaped
            If Keyin = CR THEN DunInputn
            If AllowSign then
            IF Posn = 0 THEN 
              If Keyin = "-" THEN
                  Kerror.7 = 1
                  Hserout ["-"]
                  goto GetMoreN
               endif    
               if Keyin = "+" then
                  Hserout ["+"]   
                  goto GetMoreN
               endif   
            ENDIF 
            endif   
            IF Keyin = BS THEN
                 IF POSN > 0 THEN
                  HSEROUT [BS,SP,BS]
                  POSN = POSN - 1
                  KInputString [POSN] = $FF
                  GOTO GetMoreN
               ENDIF   
            ENDIF
        iF POSN >= MaxNum THEN goto DunInputN    
        IF Keyin < "0" or Keyin > "9" THEN GetMoreN 
        HSEROUT [Keyin]
        KInputString [POSN] = Keyin - "0"
       
        POSN = POSN +1
        GOTO GetMoreN
DunInputN:
        For xN = 4 to 0 STEP - 1 
           IF KInputString[XN]= 255 THEN NotANum
             KResult = KResult + (KInputString[xN]*YY)
             YY = YY *10 
NotANum:            
       
        Next XN
        If Kerror.7 then
          If Kresult < 32768 then
               KResult = 0 - KResult
          else
               Kerror.0 = 1
               goto zeronum
          endif          
        endif  
        Return    ; success
        
DeadAtKeyboard:        
        Kerror.1 = 1
        Goto ZeroNum
        
Escaped:
       Kerror.2 = 1
        
ZeroNum:
        KResult = 0
        RETURN 
     

OverKInput:
    Note:
    No attempt has been made to prevent entries over 65535. An easy way to prevent this mistake is to set MAXNUM to 4. This will make it impossible to enter numbers over 9999.