...在单片机的P3.7口产生一个占空比为2:5周期为500ums的方波脉冲信号...答:A,R7 MOVC A,@A+DPTR MOV P3,A AJMP LOOP TIME0_1:PUSH ACC DJNZ R6,RTT MOV R6,#2 ;2次中断为100ms INC R7 ;取表加1 DJNZ R5,RTT ;中断间隔次5次,2次为高电平,3次低电平,40%占空比 MOV R5,#5 MOV R7,#0 RTT:POP ACC RETI TAB:DB 80H,80H,00H,00H,00H END ...