Inkey

Syntax

Assignment Variable = Inkey

Overview

Scan a matrix keypad and place the returned value of the button pressed.

Parameters

None Assignment Variable is a user defined variable.

Example

  Device = 24FJ64GA002             ' Select the device to compile for
  Declare Xtal = 16
  Declare Hserial_Baud = 9600       ' USART1 Baud rate
  Declare Hrsout1_Pin = PORTB.14    ' Select the pin for TX with USART1
  Declare KeyPad_Port = PORTB

  Dim MyByte as Byte
  RPOR7 = 3                      ' Make PPS Pin RP14 U1TX

  Do                              ' Create an infinite loop
     MyByte = Inkey               ' Scan the keypad
     DelayMs 50                  ' Simple debounce by waiting 50ms
     Hrsout Dec MyByte, 13        ' Display the result
  Loop                           ' Do it forever

Notes.

Inkey will return a value between 0 and 16. If no key is pressed, the value returned is 16.

Using a LookUp command, the returned values can be re-arranged to correspond with the legends printed on the keypad: -

MyByte = Inkey
MyKey = LookUp MyByte, [255,1,4,7,"*",2,5,8,0,3,6,9,"#",0,0,0]

The above example is only a demonstration, the values inside the LookUp command will need to be re-arranged for the type of keypad used, and its connection configuration.

Inkey Declare

Declare Keypad_Port Port

Assigns the 8-bits of a Port that the keypad is attached to.

The diagram above illustrates typical connections for a 16-button keypad.

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