keyboard4x3text.bas

Bascom 8051 keyboard

'ASCII input with 3x4 keyboard matrix
'This application note is written by John van der Putte.
'The program uses a 3x4 keyboard matrix to input ASCII.
'The output is placed on the LCD-display and will be saved in the variable TEXT.
'If one key is keyed several times the characters of that key rotates at the cursor.
'When no key is pressed the cursor shifts to the next display-position after a while.
'This time can easely be changed.
' *************************************************
' * MATRIXINPUT V1.0 07-12-99
' *
' * Author: John van der Putte
' * E-mail: [e-mail]
' * icq: 47666030
' *
' * Program:
' * This program uses a 3x4 keyboard matrix to input
' * ASCII. The output is placed on the LCD-display and
' * will be saved in the variable TEXT.
' * If one key is pushed several times the characters
' * of that key rotates at the cursor. When no key is
' * pressed the cursor shifts to the next display-
' * position after a while. This time can easely be changed.
' *
' * The keys have the following layout:
' *
' * 1 2 3
' * .,?!-& ABC DEF
' *
' * 4 5 6
' * GHI JKL MNO
' *
' * 7 8 9
' * PQRS TUV WXYZ
' *
' * * 0 #
' * <BACKSPACE> <SPACE> <ENTER>
' *
' *
' *
' * The procedure which looks to the keyboard matrix returns the
' * following values:
' * no key = 17
' * 0...9 = 0...9
' * * = 10
' * # = 11
' *
$romstart = &H4100
$ramstart = &H030
'$lcd = &H2000
'$map
Config Lcd = 20 * 2
Config Debounce = 25 ' Set Key Pad Debounce to 40 Ms
Col1 Alias P4.7
Col2 Alias P4.6
Col3 Alias P4.5
Row1 Alias P4.3
Row2 Alias P4.2
Row3 Alias P4.1
Row4 Alias P4.0
Dim Keyread As Byte ' key being scanned
Dim Key As Byte ' key being pressed
Dim Keyold As Byte ' key being pressed before
Dim Number As Byte ' pointer to charactertable
Dim Index As Byte ' pointer to character for the pressed key
Dim Character As String * 1 ' character selected
Dim Count As Byte ' time for automatic cursormovement
Dim Text As String * 20 ' text inputted so far
Dim I As Byte ' used by for-next loops
Dim Begin As Byte ' pointer to character in charactertable
'Dim Name As String * 2                                        'org: Dim Name As String * 20
Const Countmax = 30                                           ' change this value for different time of automatic cursormovement
Cls ' clear lcd-display
Cursor Off Blink ' no cursor but blinking character
' time for automatic cursormovement is controlled bij timer0.
' when timer0 is needed for other purposes you can replace it
' with a simple incrementation of a variable
' timer0 is configured as a 16-bit timer
Config Timer0 = Timer , Gate = Internal , Mode = 1
On Timer0 Timer_0_int
Enable Interrupts
Enable Timer0
Print "Give your textinput with keyboardmatrix."
Print "Input is displayed on LCD, result is displayed on screen"
Gosub Matrix_input
Print
Print "This is your input: >" ; Text ; "<"
End
Matrix_input:
Index = 0 ' reset index
Keyold = 16 ' reset keyold (16 is used to prevent automatic cursormovement)
Count = 0 ' reset count
Text = ""                                                     ' reset text
Do
L0:
Gosub Keyscan
L1:
If Row1 = 0 Then Goto L1
If Row2 = 0 Then Goto L1
If Row3 = 0 Then Goto L1
If Row4 = 0 Then Goto L1
If Count = Countmax Then ' if it is time for automatic cursormovement then
Shiftcursor Right ' move cursor to the right on display
Text = Text + Character ' save character in text
Stop Timer0 ' stop automatic cursormovement
Count = 0 ' reset counter
Index = 0 ' reset index
Keyold = 16                                                   ' pretend an other keypress to suppress automatic cursormovement
End If
If Key < 16 Then
If Keyold = 16 Then ' prevent automaic cursormovement
Keyold = Key
Stop Timer0
End If
If Key = 10 Then ' BACKSPACE-keywas pressed
Gosub Key10
Goto L0
End If
If Key = 11 Then Goto Key11                                   ' ENTER-key was pressed
End If
Restore Keylength ' get startpoint in keytable
Begin = 1 ' point at start of keytable
For I = 0 To Key '
Read Number ' read number of characters available on key
If I < Key Then ' calculate startpoint in keytable
Begin = Begin + Number '
End If '
Next I '
If Key <> Keyold Then ' if other key is pressed then
Index = 0 ' reset index
Shiftcursor Right ' move cursor to the right on display
Text = Text + Character ' save character in text
End If '
If Index = Number Then ' index must not exceed the numer of available characters
Index = 0 '
End If '
Begin = Begin + Index ' set pointer in keytable
Restore Keydata ' get character from keytable
For I = 1 To Begin '
Read Character '
Next I '
Lcd Character ' show character to display
Shiftcursor Left ' and move cursor to the left
Count = 0 ' reset count
Start Timer0 ' start timer for automatic cursormovement
Keyold = Key                                                  ' save the pressed key
Incr Index ' increment index
End If '
Loop
' BACKSPACE-key was pressed
Key10:
I = Len(text) ' number of characters of endresult
If I > 0 Then ' only remove character it there are characters
If Tcon.4 = 1 Then ' if timer0 is still runnuning then:
Stop Timer0 ' stop the timer
Count = 0 ' and reset counting
Lcd " " ' clear lcd at position of cursor
Shiftcursor Left ' and place cursor at the right position
Else
Shiftcursor Left ' move cursor to the left
Lcd " " ' and remove character from lcd
Shiftcursor Left ' place the cursor at the right position
Decr I ' remove last character from result
Text = Left(text , I)
If I = 0 Then ' if no more characters in result then clear result
Text = ""
End If
End If
Keyold = 16 ' prevent automatic cursormovement
End If
Return
' ENTER-key was pressed
Key11:
If Tcon.4 = 1 Then                                            ' if timer0 is still running the keypress isn't added to endresult
Text = Text + Character ' so add it now
End If
Return
Keyscan:                                                      ' Keypad Read Routine (Assignments can be changed for different connections)
Key = 17
Col1 = 0 : Col2 = 1 : Col3 = 1 ' Turns Columns On (Low) 1 by 1
Keyread = 1 : Debounce Row1 , 0 , Gotkey ' Goto if Key Pressed (Reads LOW Input)
Keyread = 4 : Debounce Row2 , 0 , Gotkey
Keyread = 7 : Debounce Row3 , 0 , Gotkey
Keyread = 10 : Debounce Row4 , 0 , Gotkey ' BACKSPACE Button *
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Col1 = 1 : Col2 = 0 : Col3 = 1
Keyread = 2 : Debounce Row1 , 0 , Gotkey
Keyread = 5 : Debounce Row2 , 0 , Gotkey
Keyread = 8 : Debounce Row3 , 0 , Gotkey
Keyread = 0 : Debounce Row4 , 0 , Gotkey
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Col1 = 1 : Col2 = 1 : Col3 = 0
Keyread = 3 : Debounce Row1 , 0 , Gotkey
Keyread = 6 : Debounce Row2 , 0 , Gotkey
Keyread = 9 : Debounce Row3 , 0 , Gotkey
Keyread = 11 : Debounce Row4 , 0 , Gotkey ' ENTER Button #

Return
Gotkey:
Key = Keyread
Return
' everytime TIMER0 overflows it generates an interrupt and jumps to this place
Timer_0_int:
Incr Count ' increment count
Return
' This table holds the number of available characters for each key (0...9)
Keylength:
Data 2 , 7 , 4 , 4 , 4 , 4 , 4 , 5 , 4 , 5
' This table holds the characters available for each key (0...9)
' If you changes this table than you must change the keylength-table too.
Keydata:
Data " " , "0"
Data "." , "," , "?" , "!" , "-" , "&" , "1"
Data "A" , "B" , "C" , "2"
Data "D" , "E" , "F" , "3"
Data "G" , "H" , "I" , "4"
Data "J" , "K" , "L" , "5"
Data "M" , "N" , "O" , "6"
Data "P" , "Q" , "R" , "S" , "7"
Data "T" , "U" , "V" , "8"
Data "W" , "X" , "Y" , "Z" , "9"