PS/2 Processing C51 Header Files

/*****Function description: PS/2 keyboard application header file (interrupt processing) *****/
/*****Debugging platform: 51 single-chip microcomputer 11.0592M crystal *****/
/*****Author: Zheng Wen (ClimberWin) *****/
/*****Written date: October 5, 2009 *****/
/*****Version information: V1.0 *****/
/*****Modified date: *****/
/*****************************************************************/
#ifndef __C51_PS_2_H__
#define __C51_PS_2_H__

#include
#define uchar unsigned char
#define uint unsigned int
////////////////Data definition///////////////////////////////////////
sbit PS2_key_Da ta= P2^0; //define PS2 Da ta pin
sbit PS2_key_CLK =P3^3; //define PS2 Clk pin
bit PS2_flag=0; //Whether there is PS/2 key data receiving flag
bit PS2_key_UP=0, Shift=0;//Whether the PS2_key_UP is released, whether the Shift key is pressed
uchar clk_num = 0; //Interrupt count, used to determine the number of bits of received data
uchar PS2_da ta; //Key value storage address
uchar LCD1602_cursor = 0; //Display cursor position
///////////////Use function definition///////////////////////////////////
void PS2_decode(unsigned char PS2_Co de);
/////////////////Data receiving subroutine (interrupt processing)///////////////////////////////
//Keyboard protocol One frame contains 11 bits of serial protocol
//bit1 :START=0
//bit2-9: data bit DA TA0-DA TA7
//bit10 : parity bit
//bit11 :STOP=1
void PS2_data_receive (void) interrupt 2
{
    clk_num++; //Increase the number of interrupts by 1
    if ((clk_num>1) && (clk_num<10))
  {    
      if(PS2_key_Da ta==0) //Bit 0 receives and saves 
   {PS2_da ta=PS2_da ta>>1 | 0x00;}
   else //Bit 1 receives and saves 
   {PS2_da ta=PS2_da ta>>1 | 0x80;}
     
  } 
 while (!PS2_key_CLK); //Wait for PS/2CLK to be pulled high
 if (clk_num > 10) //When the interrupt occurs 11 times, it means that one frame of data has been received
  {
   clk_num = 0; //Clear count value
   PS2_flag = 1; //Turn on key value flag
   EA = 0; //Turn off interrupt
  }
}
///////////////////////Key value processing subroutine ////////////////////////////////////
void PS2_decode(unsigned char PS2_Co de) //Note: if SHIFT+G is 12H 34H F0H 34H F0H 12H, that is, shift pass code + G pass code + shift break code + G break code
{
 uchar tab_num; 

 if (PS2_key_UP==0) //In the initial state
  {
   switch (PS2_Co de)
    {
     case 0xF0 : //When 0xF0 is received, PS2_key_UP is set to 1 to indicate the start of the break code
      PS2_key_UP = 1;
     break;

     case 0x12: // Left SHIFT
      Shift = 1;
     break;

     case 0x59: //Right SHIFT
      Shift = 1;
     break;

     default:      
      
      if(!Shift) //If SHIFT is not pressed
       {
        for (tab_num = 0;(UnShifted[tab_num][0]!=PS2_Co de)&&(tab_num<59); tab_num++); //Table displayif
        (UnShifted[tab_num][0] == PS2_Co de) //Key handler
       } 
      else //Press SHIFT
       {
        for(tab_num = 0; (Shifted[tab_num][0]!=PS2_Co de)&&(tab_num<59); tab_num++); //Table displayif
        (Shifted[tab_num][0] == PS2_Co de) //Key handler

       }

     break;
    }
  }
 else //When PS2_key_UP==1, that is, the key is popped up.
  { 
   PS2_key_UP = 0; //Clear flag
   if (PS2_Code ==0x12 || PS2_Code ==0x59) Shift = 0; //When the SHIFT key is pressed, it needs to be cleared
  }
 PS2_flag = 0; //The identification character is processed
}

#endif