Keypad Library
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Keypad Library

mikroBasic PRO for ARM provides a library for working with 4x4 keypad. The library routines can also be used with 4x1, 4x2, or 4x3 keypad. For connections explanation see schematic at the bottom of this page.

External dependencies of Keypad Library

Stellaris

The following variable must be defined in all projects using Keypad Library: Description : Example :
dim keypadPort as longword sfr external Keypad Port. dim keypadPort as word at GPIO_PORTH_DATA
dim keypadPort_Direction as longword sfr external Keypad Port. dim keypadPort_Direction as word at GPIO_PORTH_DIR

STM32

The following variable must be defined in all projects using Keypad Library: Description : Example :
dim keypadPort_Input as longword sfr external Keypad Input Port. dim keypadPort_Input as longword at GPIOD_IDR
dim keypadPort_Output as longword sfr external Keypad Output Port. dim keypadPort_Output as longword at GPIOD_ODR

Library Routines

Keypad_Init

Prototype

sub procedure Keypad_Init()
Description

Initializes given port for working with keypad.
Parameters

None.
Returns

Nothing.
Requires

External dependencies of the library from the top of the page must be defined before using this function.
Example

Stellaris

' Keypad module connections
dim keypadPort as byte at GPIO_PORTH_DATA
dim keypadPort_Direction as byte at GPIO_PORTH_DIR
' End Keypad module connections
...
Keypad_Init()

STM32

' Keypad module connections
dim keypadPort_Input as longword at GPIOD_IDR
dim keypadPort_Output as longword at GPIOD_ODR
' End Keypad module connections
...
Keypad_Init()
Notes

The Keypad library uses lower byte (bits <7..0>) of keypadPort.

Keypad_Key_Press

Prototype

sub function Keypad_Key_Press() as word
Description

Reads the key from keypad when key gets pressed.
Parameters

None.
Returns

The code of a pressed key (1..16).

If no key is pressed, returns 0.
Requires

Port needs to be initialized for working with the Keypad library, see Keypad_Init.
Example 
dim kp as word
...
kp = Keypad_Key_Press()
Notes

None.

Keypad_Key_Click

Prototype

sub function Keypad_Key_Click() as word
Description

Call to Keypad_Key_Click is a blocking call: the function waits until some key is pressed and released. When released, the function returns 1 to 16, depending on the key. If more than one key is pressed simultaneously the function will wait until all pressed keys are released. After that the function will return the code of the first pressed key.
Parameters

None.
Returns

The code of a clicked key (1..16).

If no key is clicked, returns 0.
Requires

Port needs to be initialized for working with the Keypad library, see Keypad_Init.
Example 
kp = Keypad_Key_Click()
Notes

None.

Library Example

The following code can be used for testing the keypad. It is written for keypad_4x3 or _4x4. The code returned by the keypad functions (1..16) is transformed into ASCII codes [0..9,A..F], and then sent to Lcd.

Stellaris

Copy Code To ClipboardCopy Code To Clipboard 
program Keypad_Test
dim kp, cnt, oldstate as byte
    txt as char[7]
    ulLoop as longword

' Keypad module connections
dim keypadPort as byte at GPIO_PORTH_DATA
dim keypadPort_Direction as byte at GPIO_PORTH_DIR
' End Keypad module connections

' Lcd module connections
dim LCD_RS as sbit at GPIO_PORTD_DATA.B2
    LCD_EN as sbit at GPIO_PORTD_DATA.B3
    LCD_D4 as sbit at GPIO_PORTD_DATA.B4
    LCD_D5 as sbit at GPIO_PORTD_DATA.B5
    LCD_D6 as sbit at GPIO_PORTD_DATA.B6
    LCD_D7 as sbit at GPIO_PORTD_DATA.B7

    LCD_RS_Direction as sbit at GPIO_PORTD_DIR.B2
    LCD_EN_Direction as sbit at GPIO_PORTD_DIR.B3
    LCD_D4_Direction as sbit at GPIO_PORTD_DIR.B4
    LCD_D5_Direction as sbit at GPIO_PORTD_DIR.B5
    LCD_D6_Direction as sbit at GPIO_PORTD_DIR.B6
    LCD_D7_Direction as sbit at GPIO_PORTD_DIR.B7
' End Lcd module connections


main:

    oldstate = 0
    cnt = 0                             ' Reset counter
    Keypad_Init()                       ' Initialize Keypad
    Lcd_Init()                          ' Initialize LCD
    Lcd_Cmd(_LCD_CLEAR)                 ' Clear display
    Lcd_Cmd(_LCD_CURSOR_OFF)            ' Cursor off
    Lcd_Out(1, 1, "Key  :")             ' Write message text on LCD
    Lcd_Out(2, 1, "Times:")

    while TRUE

      kp = 0                            ' Reset key code variable

      ' Wait for key to be pressed and released
      while ( kp = 0 )
        kp = Keypad_Key_Click()         ' Store key code in kp variable
      wend
      ' Prepare value for output, transform key to it"s ASCII value
      select case kp
        'case 10: kp = 42   ' "*"       ' Uncomment this block for keypad4x3
        'case 11: kp = 48   ' "0"
        'case 12: kp = 35   ' "#"
        'default: kp += 48

      case 1
        kp = 49  ' 1                    ' Uncomment this block for keypad4x4
      case 2
        kp = 50  ' 2
      case 3
        kp = 51  ' 3
      case 4
        kp = 65  ' A
      case 5
        kp = 52  ' 4
      case 6
        kp = 53  ' 5
      case 7
        kp = 54  ' 6
      case 8
        kp = 66  ' B
      case 9
        kp = 55  ' 7
      case 10
        kp = 56  ' 8
      case 11
        kp = 57  ' 9
      case 12
        kp = 67  ' C
      case 13
        kp = 42  ' *
      case 14
        kp = 48  ' 0
      case 15
        kp = 35  ' #
      case 16
        kp = 68  ' D

      end select

      if (kp <> oldstate) then        ' Pressed key differs from previous
        cnt = 1
        oldstate = kp
      else                            ' Pressed key is same as previous
        Inc(cnt)
      end if
      Lcd_Chr(1, 10, kp)              ' Print key ASCII value on LCD

      if (cnt = 255) then             ' If counter varialble overflow
        cnt = 0
        Lcd_Out(2, 8, "     ")
      end if

      ByteToStr(cnt, txt)             ' Transform counter value to string
      Lcd_Out(2, 8, txt)             ' Display counter value on LCD
    wend
end.

STM32

Copy Code To ClipboardCopy Code To Clipboard 
program Keypad_Test

dim kp, cnt, oldstate as byte
    txt as char[7]
    ulLoop as longword

' Keypad module connections
dim keypadPort_Input  as longword at GPIOD_IDR
dim keypadPort_Output as longword at GPIOD_ODR
' End Keypad module connections

' Lcd module connections
dim LCD_RS as sbit at GPIOD_ODR.B10
    LCD_EN as sbit at GPIOD_ODR.B11
    LCD_D4 as sbit at GPIOD_ODR.B12
    LCD_D5 as sbit at GPIOD_ODR.B13
    LCD_D6 as sbit at GPIOD_ODR.B14
    LCD_D7 as sbit at GPIOD_ODR.B15
' End Lcd module connections


main:
  oldstate = 0
  cnt = 0                             ' Reset counter
  Keypad_Init()                       ' Initialize Keypad
  Lcd_Init()                          ' Initialize LCD
  Lcd_Cmd(_LCD_CLEAR)                 ' Clear display
  Lcd_Cmd(_LCD_CURSOR_OFF)            ' Cursor off
  Lcd_Out(1, 1, "Key  :")             ' Write message text on LCD
  Lcd_Out(2, 1, "Times:")

  while TRUE

    kp = 0                            ' Reset key code variable

    ' Wait for key to be pressed and released
    while ( kp = 0 )
      kp = Keypad_Key_Click()         ' Store key code in kp variable
    wend
    
    ' Prepare value for output, transform key to it"s ASCII value
    select case kp
      'case 10: kp = 42   ' "*"       ' Uncomment this block for keypad4x3
      'case 11: kp = 48   ' "0"
      'case 12: kp = 35   ' "#"
      'default: kp += 48

      case 1
        kp = 49  ' 1                  ' Uncomment this block for keypad4x4
      case 2
        kp = 50  ' 2
      case 3
        kp = 51  ' 3
      case 4
        kp = 65  ' A
      case 5
        kp = 52  ' 4
      case 6
        kp = 53  ' 5
      case 7
        kp = 54  ' 6
      case 8
        kp = 66  ' B
      case 9
        kp = 55  ' 7
      case 10
        kp = 56  ' 8
      case 11
        kp = 57  ' 9
      case 12
        kp = 67  ' C
      case 13
        kp = 42  ' *
      case 14
        kp = 48  ' 0
      case 15
        kp = 35  ' #
      case 16
        kp = 68  ' D
    end select

    if (kp <> oldstate) then        ' Pressed key differs from previous
      cnt = 1
      oldstate = kp
    else                            ' Pressed key is same as previous
      Inc(cnt)
    end if
    Lcd_Chr(1, 10, kp)              ' Print key ASCII value on LCD

    if (cnt = 255) then             ' If counter varialble overflow
      cnt = 0
      Lcd_Out(2, 8, "     ")
    end if

    ByteToStr(cnt, txt)             ' Transform counter value to string
    Lcd_Out(2, 8, txt)              ' Display counter value on LCD
  wend
end.
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