利用89C51的P1口控制8个发光二极管LED｡相邻的4个LED为一组,使2组每隔0.5s 交替发亮一次,周而复始｡试编写程序｡

ORG 0100H MOV A,#0FH ABC: MOV P1,A ACALL D05 SWAP A SJMP ABC D05: MOV R6,250 DY: MOV R7,250 DAY: NOP NOP DJNZ R6,DAY DJNZ R7,DY RET END