一，happy birthday 生日快乐歌用21个音阶设计的程序
Void happy birthday()要用C51格式写程序！
{
setb tr0（tr0=1;）                   ；启动定时器0
start0:
setb p3.3;
30h=0x00;
next:
mov a,30h
mov dptr,#table
inc dptr
movc a,@a+dptr
mov r5,a                    ；将节拍码存入r5
cjne a,#0ffh,next1
jmp ennd
next1:
clr c
mov a,dpl
subb a,#1
mov dpl,a
mov a,dph
subb a,#0
mov dph,a
mov a,30h
movc a,@a+dptr
jnz sing
clr tr0                      ；休止符？是，则不发音
jmp d1                       ；跳到d1
sing:
dec a                        ；取到的音符码减1
mov 22h,a                    ；存入（22h)
rl a                         ； 乘2
mov dptr,#table1             ；至table1取相对应的高字节
movc a,@a+dptr                
mov th0,a                    ；取到的高字节存入TH0
mov 21h,a                    ；取到的高字节存入（21h)
mov a,22h                    ；乘2
rl a                         ；加1
inc a                        ；至table1取相对应的低位
movc a,@a+dptr                              
mov tl0,a                    ；取到低字节存入tl0                  
mov 20h,a                    ；取到低字节存入（20h)
setb tr0                     ；启动timer0
d1:
call delay                   ；声音延时   基本单位时间 1/4拍187毫秒
inc 30h                      ；取简码简指针加1
inc 30h                      ；取简码简指针加1
jmp next                     ；取下一个码
ennd:
clr tr0                      ；停止timer0
ret
table:
db 12,2,0,1,12,2,13,4,12,4,15,4,14,4,0,4
db 12,2,0,1,12,1,13,4,12,4,16,4,15,4,0,4
db 12,2,0,1,12,1,19,4,17,4,15,4,14,4,13,4
db 18,2,0,1,18,1,17,4,15,4,16,4,15,4,0,4
db 12,2,0,1,12,1,13,4,12,4,15,4,14,4,0,4
db 12,2,0,1,12,1,13,4,12,4,16,4,15,4,0,4
db 12,2,0,1,12,1,19,4,17,4,15,4,14,4,13,4
db 18,2,0,1,15,1,17,4,15,4,16,4,15,4,0,4,0ffh,0ffh

}