电子琴汇编程序

 BUZZ     EQU P1.0
       ORG      0000H
       LJMP     MAIN
       ORG      000BH
       LJMP     INT_T0
       ORG      0100H
MAIN:   
       MOV      SP,#60H        ;初始化堆栈指针
       MOV      30H,#00        ;定时器初值清零
       MOV      31H,#00
       MOV      P1,#0FFH       ;设置P1口为输入模式
       MOV      TMOD,#01H      ;设置定时器0为工作模式1
       SETB     ET0            ;开定时器0中断
       SETB     EA             ;开总中断
       CLR      TR0            ;关闭定时器0 
START:  
       MOV      R0,P2       
       CJNE     R0,#0FFH,KEY1  ;键盘扫描
       CLR      TR0
       SJMP     START
KEY1:
       CJNE     R0,#0FEH,KEY2  ;K1键按下
       MOV      30H,#0FBH      ;设置音阶1
       MOV      31H,#0E9H
       LJMP     SET_TIMER
KEY2:   
       CJNE     R0,#0FDH,KEY3  ;K2键按下
       MOV      30H,#0FCH      ;设置音阶2
       MOV      31H,#5CH
       LJMP     SET_TIMER