keypad avr schematic
Action
Configure the GETKBD() function and tell which port to use.
Syntax
CONFIG KBD = PORTx , DEBOUNCE = value [, DELAY = value]
Remarks
| PORTx | The name of the PORT to use such as PORTB or PORTD. |
| DEBOUNCE | By default the debounce value is 20. A higher value might be needed. The maximum is 255. |
| Delay | An optional parameter that will cause Getkbd() to wait the specified amount of time after the key is detected. This parameter might be added when you call GetKbd() repeatedly in a loop. Because of noise and static electricity, wrong values can be returned. A delay of say 100 mS, can eliminate this problem. |
The GETKBD() function can be used to read the pressed key from a matrix keypad attached to a port of the uP.
You can define the port with the CONFIG KBD statement.
In addition to the default behavior you can configure the keyboard to have 6 rows instead of 4 rows.
CONFIG KBD = PORTx , DEBOUNCE = value , rows=6, row5=pinD.6, row6=pind.7
This would specify that row5 is connected to pind.6 and row7 to pind.7
Note that you can only use rows=6. Other values will not work.
See also
Example
‘—————————————————————————————–
‘name : getkbd.bas
‘copyright : (c) 1995-2005, MCS Electronics
‘purpose : demo : GETKBD
‘micro : Mega48
‘suited for demo : yes
‘commercial addon needed : no
‘—————————————————————————————–
$regfile = “m48def.dat” ‘ specify the used micro
$crystal = 4000000 ‘ used crystal frequency
$baud = 19200 ‘ use baud rate
$hwstack = 32 ‘ default use 32 for the hardware stack
$swstack = 10 ‘ default use 10 for the SW stack
$framesize = 40 ‘ default use 40 for the frame space
‘specify which port must be used
‘all 8 pins of the port are used
Config Kbd = Portb
‘dimension a variable that receives the value of the pressed key
Dim B As Byte
‘loop for ever
Do
B = Getkbd()
‘look in the help file on how to connect the matrix keyboard
‘when you simulate the getkbd() it is important that you press/click the keyboard button
‘ before running the getkbd() line !!!
Print B
‘when no key is pressed 16 will be returned
‘use the Lookup() function to translate the value to another one
‘ this because the returned value does not match the number on the keyboad
Loop
End
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