How to read the computer keyboard with PICmicrocontrollers?

[amindzo]

Hi, i want to read the keyboard of the computer with PIC16F877A.
could you help me how to do it?

 

[Nigel Goodwin]

Check the EPE website, they did a project on it a number of years ago, or check the PICList, they have code as well - or google, there's plenty of code out there!.

 

[gramo]

Download mikroBasic and search for "keyboard" or "PS/2" with the help file search tool.

It has a complete set of integrated tools for PS/2 keyboard control

 

[blueroomelectronics]

Hey Gramo, thought you don't like MicroBASIC?

PS here's a schematic and .asm code for PS/2 to keyboard.
https://www.electronic-engineering.ch/microchip/projects/keyboard/v3xx/keyboard_v3xx.html

 

[gramo]

Hey Gramo, thought you don't like MicroBASIC?

They do however offer a lot of modules (like PS/2)

 

[gramo]

From the help file;

This simple example reads values of keys pressed on PS/2 keyboard and sends them via USART.

program ps2_test
dim keydata, special, down as byte

main:
  CMCON  = $07           ' Disable analog comparators (comment this for P18)
  INTCON = 0             ' Disable all interrupts
  Ps2_Init(PORTA)        ' Init PS/2 Keyboard on PORTA
  Delay_ms(100)          ' Wait for keyboard to finish

  do
    if Ps2_Key_Read(keydata, special, down) = 1 then
      if (down = 1) and (keydata = 16) then  ' Backspace
        ' ...do something with a backspace...
      else
        if (down = 1) and (keydata = 13) then  ' Enter
          Usart_Write(13)
        else
          if (down = 1) and (special = 0) and (keydata <> 1) then
            Usart_Write(keydata)
          end if
        end if
      end if
    end if
    Delay_ms(10)    ' debounce
  loop until FALSE
end.

The PS2_Init function will tell the compiler how the keyboard is connected

Ps2_Init(dim byref port as byte)

Initializes port for work with PS/2 keyboard, with default pin settings. Port pin 0 is Data line, and port pin 1 is Clock line.

You need to call either Ps2_Init or Ps2_Config before using other routines of PS/2 library.

 

[csaba911]

**broken link removed**

Have fun

 

[amindzo]

thank you every body. i will examine all of the answrs and tell you if i have a problem.