MOV TCOUNT,#00H MOV TMOD,#01H
MOV TH0,#(65536-50000) / 256 MOV TL0,#(65536-50000) MOD 256 SETB TR0 SETB ET0 SETB EA SJMP $ INT0X:
MOV TH0,#(65536-50000) / 256 MOV TL0,#(65536-50000) MOD 256 INC TCOUNT MOV A,TCOUNT CJNE A,#20,NEXT MOV TCOUNT,#00H INC SECOND MOV A,SECOND CJNE A,#60,NEX MOV SECOND,#00H NEX: MOV A,SECOND MOV B,#10 DIV AB
MOV DPTR,#TABLE MOVC A,@A+DPTR MOV P0,A MOV A,B
MOVC A,@A+DPTR MOV P2,A NEXT: RETI
TABLE: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH END
2． C语言源程序（中断法） #include <AT89X51.H>
unsigned char code dispcode[]={0x3f,0x06,0x5b,0x4f, 0x66,0x6d,0x7d,0x07, 0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x71,0x00}; unsigned char second; unsigned char tcount;
void main(void) {