51单片机 汇编 IO音乐系列 八音盒 org 0000h ajmp main org 000bh ajmp timer0 org 0030h timer0: clr ea djnz 33h,exit mov 33h,53h djnz 32h,exit mov 32h,52h djnz 31h,exit1 mov 31h,51h djnz 30h,exit1 setb f0 ajmp exit exit1: cpl p3.3 exit: setb ea reti main: mov tmod,#02h mov ie,#82h mov th0,#254 mov tl0,#254 mov dptr,#tab main1: mov 40h,#00h loop: clr ea mov a,40h movc a,@a+dptr mov 30h,a mov 50h,a inc 40h mov a,40h movc a,@a+dptr mov 31h,a mov 51h,a inc 40h mov a,40h movc a,@a+dptr mov 32h,a mov 52h,a inc 40h mov a,40h movc a,@a+dptr mov 33h,a mov 53h,a setb ea setb tr0 jnb f0,$ clr f0 inc 40h mov a,40h cjne a,#40,loop ajmp main1 tab: ; 30h,31h,32h,33h db 2,25,24,16 ;low frequency