void Keyboard_out(void) interrupt 2
{
if ((IntNum > 0) && (IntNum < 9))
{ 
KeyV = KeyV >> 1; //因鍵盤數據是低>>高，結合上一句所以右移一位
if (Key_Data) KeyV = KeyV | 0x80; //當鍵盤數據線為1時為1到最高位
}
IntNum++;
while (!Key_CLK); //等待PS/2CLK拉高

if (IntNum > 10)
{
IntNum = 0; //當中斷11次后表示一幀數據收完，清變量準備下一次接收
BF = 1; //標識有字符輸入完了
EA = 0; //關中斷等顯示完后再開中斷 (注：如這里不用BF和關中斷直接調Decode()則所Decode中所調用的所有函數要聲明為再入函數)
}
}

void Decode(unsigned char ScanCode) //注意:如SHIFT+G為12H 34H F0H 34H F0H 12H，也就是說shift的通碼+G的通碼+shift的斷碼+G的斷碼
{
unsigned char TempCyc; 

if (!Key_UP) //當鍵盤松開時
{
switch (ScanCode)
{
case 0xF0 : // 當收到0xF0，Key_UP置1表示斷碼開始
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沒按下
{
for (TempCyc = 0;(UnShifted[TempCyc][0]!=ScanCode)&&(TempCyc<59); TempCyc++); //查表顯示
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++); //查表顯示
if (Shifted[TempCyc][0] == ScanCode) DisplayOneChar(DisNum, 1, Shifted[TempCyc][1]);
DisNum++;
}

break;
}
}
else
{ 
Key_UP = 0;
switch (ScanCode) //當鍵松開時不處理判碼，如G 34H F0H 34H 那么第二個34H不會被處理
{
case 0x12 : // 左 SHIFT
Shift = 0;
break;

case 0x59 : // 右 SHIFT
Shift = 0;
break;
}
}
BF = 0; //標識字符處理完了
} 

scancodes.h

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',
};