lcddata nsigned字符列，页，code_，K

代码说明：

nsigned char lcddata,column,page,code_,k xdata unsigned char OUTBIT _at_ 0x2001 // 位控制口 xdata unsigned char IN _at_ 0x2002 // 键盘读入口 xdata unsigned char CONTROL _at_ 0x2003 //8255控制口 -nsigned char lcddata, column, page, code_, k xdata unsigned char OUTBIT _at_ 0x2001// bit control port xdata unsigned char IN _at_ 0x2002// keyboard Reading entrance xdata unsigned char CONTROL _at_ 0x2003// 8255 to control population