Keypad Library

mikroPascal 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 :
`var keypadPort : dword; sfr; external;`	Keypad Port.	`var keypadPort : byte at GPIO_PORTH_DATA;`
`var keypadPort_Direction : dword; sfr; external;`	Keypad Port.	`var keypadPort_Direction : byte at GPIO_PORTH_DIR;`

STM32

The following variable must be defined in all projects using Keypad Library:	Description :	Example :
`var keypadPort_Input : dword; sfr; external;`	Keypad Port.	`var keypadPort_Input : dword at GPIOD_IDR;`
`var keypadPort_Output : dword; sfr; external;`	Keypad Port.	`var keypadPort_Output : dword at GPIOD_ODR;`

Keypad_Init

Prototype	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 var keypadPort : byte at GPIO_PORTH_DATA; var keypadPort_Direction : byte at GPIO_PORTH_DIR; // End Keypad module connections ... Keypad_Init(); STM32 // Keypad module connections var keypadPort_Input: dword at GPIOD_IDR; var keypadPort_Output: dword 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	function Keypad_Key_Press(): 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	var kp : word; ... kp := Keypad_Key_Press();
Notes	None.

Keypad_Key_Click

Prototype	function Keypad_Key_Click(): 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 via UART1.

Stellaris

Copy Code To Clipboard

program Keypad_Test;
var kp, cnt, oldstate : byte;
    txt : array[6] of char;

// Keypad module connections
var keypadPort : byte at GPIO_PORTH_DATA;
var keypadPort_Direction : byte at GPIO_PORTH_DIR;
// End Keypad module connections


// Lcd module connections
var LCD_RS : sbit at GPIO_PORTD_DATA.B2;
    LCD_EN : sbit at GPIO_PORTD_DATA.B3;
    LCD_D4 : sbit at GPIO_PORTD_DATA.B4;
    LCD_D5 : sbit at GPIO_PORTD_DATA.B5;
    LCD_D6 : sbit at GPIO_PORTD_DATA.B6;
    LCD_D7 : sbit at GPIO_PORTD_DATA.B7;

var LCD_RS_Direction : sbit at GPIO_PORTD_DIR.B2;
    LCD_EN_Direction : sbit at GPIO_PORTD_DIR.B3;
    LCD_D4_Direction : sbit at GPIO_PORTD_DIR.B4;
    LCD_D5_Direction : sbit at GPIO_PORTD_DIR.B5;
    LCD_D6_Direction : sbit at GPIO_PORTD_DIR.B6;
    LCD_D7_Direction : sbit at GPIO_PORTD_DIR.B7;
// End Lcd module connections


var  ulLoop: dword;
begin

    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 do
      begin
        kp := 0;                             // Reset key code variable

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

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

        end;

        if (kp <> oldstate) then         // Pressed key differs from previous
          begin
            cnt := 1;
            oldstate := kp;
          end
        else                             // Pressed key is same as previous
          Inc(cnt);

        Lcd_Chr(1, 10, kp);              // Print key ASCII value on LCD

        if (cnt = 255) then              // If counter varialble overflow
          begin
            cnt := 0;
            Lcd_Out(2, 8, '     ');
          end;

        ByteToStr(cnt, txt);             // Transform counter value to string


        Lcd_Out(2, 8, txt);             // Display counter value on LCD
    end;
  end.

STM32

Copy Code To Clipboard

program Keypad_Test;
var kp, cnt, oldstate : byte;
    txt : array[6] of char;

// Keypad module connections
var keypadPort_Input:  dword at GPIOD_IDR;
var keypadPort_Output: dword at GPIOD_ODR;
// End Keypad module connections


// Lcd module connections
var LCD_RS : sbit at GPIOD_ODR.B10;
    LCD_EN : sbit at GPIOD_ODR.B11;
    LCD_D4 : sbit at GPIOD_ODR.B12;
    LCD_D5 : sbit at GPIOD_ODR.B13;
    LCD_D6 : sbit at GPIOD_ODR.B14;
    LCD_D7 : sbit at GPIOD_ODR.B15;
// End Lcd module connections

var  ulLoop: dword;
begin

  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 do
    begin
      kp := 0;                             // Reset key code variable

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

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

      end;

      if (kp <> oldstate) then         // Pressed key differs from previous
        begin
          cnt := 1;
          oldstate := kp;
        end
      else                             // Pressed key is same as previous
        Inc(cnt);

      Lcd_Chr(1, 10, kp);              // Print key ASCII value on LCD

      if (cnt = 255) then              // If counter varialble overflow
        begin
          cnt := 0;
          Lcd_Out(2, 8, '     ');
        end;

      ByteToStr(cnt, txt);             // Transform counter value to string


      Lcd_Out(2, 8, txt);             // Display counter value on LCD
  end;
end.

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