单片机计数器T0作定时技术
6．汇编源程序（查询法）
SECOND EQU 30H
TCOUNT EQU 31H
ORG 00H
START: MOV SECOND,#00H
MOV TCOUNT,#00H
MOV TMOD,#01H
MOV TH0,#(65536-50000) / 256
MOV TL0,#(65536-50000) MOD 256
SETB TR0
DISP: 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
WAIT: JNB TF0,WAIT
CLR TF0
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: LJMP DISP
NEXT: LJMP WAIT
TABLE: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH
END
7． C语言源程序（查询法）
#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)
{
TMOD=0x01;
TH0=(65536-50000)/256;
TL0=(65536-50000)%6;
TR0=1;
tcount=0;
second=0;
P0=dispcode[second/10];
P2=dispcode[second];
while(1)
{
if(TF0==1)
{
tcount++;
if(tcount==20)
{
tcount=0;
second++;
if(second==60)
{
second=0;
}
P0=dispcode[second/10];
P2=dispcode[second];
}
TF0=0;
TH0=(65536-50000)/256;
TL0=(65536-50000)%6;
}
}
}
加入微信
获取电子行业最新资讯
搜索微信公众号：EEPW
或用微信扫描左侧二维码