单片机与PS/2键盘应用实例

SMC1602A(16*2)模拟口线接线方式
连接线图:

------------------------------------------------
   |LCM-----51   | LCM-----51   | LCM------51      |
   |-------------|--------------|------------------|
   |DB0-----P1.0 | DB4-----P1.4 | RW-------P2.0    |
   |DB1-----P1.1 | DB5-----P1.5 | RS-------P2.1    |
   |DB2-----P1.2 | DB6-----P1.6 | E--------P2.2    |
   |DB3-----P1.3 | DB7-----P1.7 | VLCD接1K电阻到GND|
   -------------------------------------------------

PS/2的电气特性如下（电脑端）：

Keyboard接线
    PS/2--------51单片机
    1 DATA------P3.4
    2 不接
    3 GND
    4 VCC
    5 CLK-------P3.3 接在51的外部中断，触发方式为低电平
    6 不接

本程序源码只供学习参考，不得应用于商业用途，如有需要请联系作者。

[注:AT89x51使用12M或11.0592M晶振,实测使用11.0592M]
[Keil uV2 7.01编译运行通过 程序中没有做键盘数据的奇偶校验]

[站长在AT89S51+12M晶振+JHD 162A液晶上调试通过]

=============================================================*/

#include "reg51.h"
#include "scancodes.h"

#define LCM_RW  P2_0//定义LCD引脚
#define LCM_RS  P2_1
#define LCM_E   P2_2
#define LCM_Data  P1

#define Key_Data P3_4//定义Keyboard引脚
#define Key_CLK  P3_3

#define Busy    0x80//用于检测LCM状态字中的Busy标识

void LCMInit(void);
void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData);
void DisplayListChar(unsigned char X, unsigned char Y, unsigned char code *DData);
void Delay5Ms(void);
void Delay400Ms(void);
void Decode(unsigned char ScanCode);
void WriteDataLCM(unsigned char WDLCM);
void WriteCommandLCM(unsigned char WCLCM,BuysC);

unsigned char ReadDataLCM(void);
unsigned char ReadStatusLCM(void);
unsigned char code cdle_net[] = {"www.cdle.net--"};
unsigned char code email[] = {"pnzwzw@cdle.net"};
unsigned char code Cls[] = {"                "};
static unsigned char IntNum = 0;//中断次数计数
static unsigned char KeyV;//键值
static unsigned char DisNum = 0;//显示用指针
static unsigned char Key_UP=0, Shift = 0;//Key_UP是键松开标识，Shift是Shift键按下标识
static unsigned char BF = 0;//标识是否有字符被收到

void main(void)
{
        unsigned char TempCyc;
        
        Delay400Ms();//启动等待，等LCM讲入工作状态
        LCMInit();//LCM初始化
        Delay5Ms();//延时片刻(可不要)
        
        DisplayListChar(0, 0, cdle_net);
        DisplayListChar(0, 1, email);
        ReadDataLCM();//测试用句无意义
        for (TempCyc=0; TempCyc<10; TempCyc++)
        Delay400Ms();//延时
        DisplayListChar(0, 1, Cls);
        
        IT1 = 0;//设外部中断1为低电平触发
        EA = 1;
        EX1 = 1;//开中断
        
        do
        {
                if (BF)
                Decode(KeyV);
                else
                EA = 1;//开中断
        }
        while(1);
}

//写数据
void WriteDataLCM(unsigned char WDLCM)
{
        ReadStatusLCM();//检测忙
        LCM_Data = WDLCM;
        LCM_RS = 1;
        LCM_RW = 0;
        LCM_E = 0;//若晶振速度太高可以在这后加小的延时
        LCM_E = 0;//延时
        LCM_E = 1;
}

//写指令
void WriteCommandLCM(unsigned char WCLCM,BuysC)//BuysC为0时忽略忙检测
{
        if (BuysC) ReadStatusLCM();//根据需要检测忙
        LCM_Data = WCLCM;
        LCM_RS = 0;
        LCM_RW = 0;
        LCM_E = 0;
        LCM_E = 0;
        LCM_E = 1;
}

//读数据
unsigned char ReadDataLCM(void)
{
        LCM_RS = 1;
        LCM_RW = 1;
        LCM_E = 0;
        LCM_E = 0;
        LCM_E = 1;
        return(LCM_Data);
}

//读状态
unsigned char ReadStatusLCM(void)
{
        LCM_Data = 0xFF;
        LCM_RS = 0;
        LCM_RW = 1;
        LCM_E = 0;
        LCM_E = 0;
        LCM_E = 1;
        while (LCM_Data & Busy);//检测忙信号
        return(LCM_Data);
}

void LCMInit(void)//LCM初始化
{
        LCM_Data = 0;
        WriteCommandLCM(0x38,0);//三次显示模式设置，不检测忙信号
        Delay5Ms();
        WriteCommandLCM(0x38,0);
        Delay5Ms();
        WriteCommandLCM(0x38,0);
        Delay5Ms();
        
        WriteCommandLCM(0x38,1);//显示模式设置,开始要求每次检测忙信号
        WriteCommandLCM(0x08,1);//关闭显示
        WriteCommandLCM(0x01,1);//显示清屏
        WriteCommandLCM(0x06,1);// 显示光标移动设置
        WriteCommandLCM(0x0F,1);// 显示开及光标设置
}

//按指定位置显示一个字符
void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData)
{
        Y &= 0x1;
        X &= 0xF;//限制X不能大于15，Y不能大于1
        if (Y) X |= 0x40;//当要显示第二行时地址码+0x40;
        X |= 0x80;//算出指令码
        WriteCommandLCM(X, 1);//发命令字
        WriteDataLCM(DData);//发数据
}

//按指定位置显示一串字符
void DisplayListChar(unsigned char X, unsigned char Y, unsigned char code *DData)
{
        unsigned char ListLength;
        
        ListLength = 0;
        Y &= 0x1;
        X &= 0xF;//限制X不能大于15，Y不能大于1
        while (DData[ListLength]>0x19)//若到达字串尾则退出
        {
                if (X <= 0xF)//X坐标应小于0xF
                {
                        DisplayOneChar(X, Y, DData[ListLength]);//显示单个字符
                        ListLength++;
                        X++;
                }
        }
}

//5ms延时
void Delay5Ms(void)
{
        unsigned int TempCyc = 5552;
        while(TempCyc--);
}

//400ms延时
void Delay400Ms(void)
{
        unsigned char TempCycA = 5;
        unsigned int TempCycB;
        while(TempCycA--)
        {
                TempCycB=7269;
                while(TempCycB--);
        };
}

void Keyboard_out(void) interrupt 2
{
        if ((IntNum > 0) && (IntNum < 9))
        {
                KeyV = KeyV >> 1;//因键盘数据是低>>高，结合上一句所以右移一位
                if (Key_Data) KeyV = KeyV | 0x80;//当键盘数据线为1时为1到最高位
        }
        IntNum++;
        while (!Key_CLK);//等待PS/2CLK拉高
        
        if (IntNum > 10)
        {
                IntNum = 0;//当中断10次后表示一帧数据收完，清变量准备下一次接收
                BF = 1;//标识有字符输入完了
                EA = 0;//关中断等显示完后再开中断 (注：如这里不用BF和关中断直接调Decode()则所Decode中所调用的所有函数要声明为再入函数)
        }
}

void Decode(unsigned char ScanCode)//注意:如SHIFT+G为12H 34H F0H 34H F0H 12H，也就是说shift的通码+G的通码+shift的断码+G的断码
{
        unsigned char TempCyc;
        
        if (!Key_UP)//当键盘松开时
        {
                switch (ScanCode)
                {
                        case 0xF0 :// 当收到0xF0，Key_UP置1表示断码开始
                        Key_UP = 1;
                        break;
                        
                        case 0x12 :// 左 SHIFT
                        Shift = 1;
                        break;
                        
                        case 0x59 :// 右 SHIFT
                        Shift = 1;
                        break;
                        
                        default:
                        if (DisNum > 15)
                        {
                                DisplayListChar(0, 1, Cls);//清LCD第二行
                                DisNum = 0;
                        }
                        if(!Shift)//如果SHIFT没按下
                        {
                                for (TempCyc = 0;(UnShifted[TempCyc][0]!=ScanCode)&&(TempCyc<59); TempCyc++);//查表显示
                                if (UnShifted[TempCyc][0] == ScanCode) DisplayOneChar(DisNum, 1, UnShifted[TempCyc][1]);
                                DisNum++;
                        }
                        else//按下SHIFT
                        {
                                for(TempCyc = 0; (Shifted[TempCyc][0]!=ScanCode)&&(TempCyc<59); TempCyc++);//查表显示
                                if (Shifted[TempCyc][0] == ScanCode) DisplayOneChar(DisNum, 1, Shifted[TempCyc][1]);
                                DisNum++;
                        }
                        
                        break;
                }
        }
        else
        {
                Key_UP = 0;
                switch (ScanCode)//当键松开时不处理判码，如G 34H F0H 34H 那么第二个34H不会被处理
                {
                        case 0x12 :// 左 SHIFT
                        Shift = 0;
                        break;
                        
                        case 0x59 :// 右 SHIFT
                        Shift = 0;
                        break;
                }
        }
        BF = 0;//标识字符处理完了
}

以下为 scancodes.h 文件
unsigned char code UnShifted[59][2] = {
        0x1C, 'a',
        0x32, 'b',
        0x21, 'c',
        0x23, 'd',
        0x24, 'e',
        0x2B, 'f',
        0x34, 'g',
        0x33, 'h',
        0x43, 'i',
        0x3B, 'j',
        0x42, 'k',
        0x4B, 'l',
        0x3A, 'm',
        0x31, 'n',
        0x44, 'o',
        0x4D, 'p',
        0x15, 'q',
        0x2D, 'r',
        0x1B, 's',
        0x2C, 't',
        0x3C, 'u',
        0x2A, 'v',
        0x1D, 'w',
        0x22, 'x',
        0x35, 'y',
        0x1A, 'z',
        0x45, '0',
        0x16, '1',
        0x1E, '2',
        0x26, '3',
        0x25, '4',
        0x2E, '5',
        0x36, '6',
        0x3D, '7',
        0x3E, '8',
        0x46, '9',
        0x0E, '`',
        0x4E, '-',
        0x55, '=',
        0x5D, '\\',
        0x29, ' ',
        0x54, '[',
        0x5B, ']',
        0x4C, ';',
        0x52, '\'',
        0x41, ',',
        0x49, '.',
        0x4A, '/',
        0x71, '.',
        0x70, '0',
        0x69, '1',
        0x72, '2',
        0x7A, '3',
        0x6B, '4',
        0x73, '5',
        0x74, '6',
        0x6C, '7',
        0x75, '8',
        0x7D, '9',
};

unsigned char code Shifted[59][2] = {
        0x1C, 'A',
        0x32, 'B',
        0x21, 'C',
        0x23, 'D',
        0x24, 'E',
        0x2B, 'F',
        0x34, 'G',
        0x33, 'H',
        0x43, 'I',
        0x3B, 'J',
        0x42, 'K',
        0x4B, 'L',
        0x3A, 'M',
        0x31, 'N',
        0x44, 'O',
        0x4D, 'P',
        0x15, 'Q',
        0x2D, 'R',
        0x1B, 'S',
        0x2C, 'T',
        0x3C, 'U',
        0x2A, 'V',
        0x1D, 'W',
        0x22, 'X',
        0x35, 'Y',
        0x1A, 'Z',
        0x45, '0',
        0x16, '1',
        0x1E, '2',
        0x26, '3',
        0x25, '4',
        0x2E, '5',
        0x36, '6',
        0x3D, '7',
        0x3E, '8',
        0x46, '9',
        0x0E, '~',
        0x4E, '_',
        0x55, '+',
        0x5D, '|',
        0x29, ' ',
        0x54, '{',
        0x5B, '}',
        0x4C, ':',
        0x52, '"',
        0x41, '<',
        0x49, '>',
        0x4A, '?',
        0x71, '.',
        0x70, '0',
        0x69, '1',
        0x72, '2',
        0x7A, '3',
        0x6B, '4',
        0x73, '5',
        0x74, '6',
        0x6C, '7',
        0x75, '8',
        0x7D, '9',
};