[size=+2]"內容 | 終點站 > [size=+0]最後更新,2542年11月4日 作者: uucww 時間: 2006-8-16 13:43 http://chaokhun.kmitl.ac.th/~kswichit/2051/7-seg/7-seg.htm
[size=+1]7-SEG.C
[size=+1]7-SEG.HEX
[size=+1]The program demonstrates simple counting down clock. S1 is used for setting time to 99, S2 for start count down.
/*
* 7-seg.c
* Driving 2-digit 7-segment Common Anode LED & keypad
* Copyright (C) 1999 Wichit Sirichote
* compiled with Dunfield Micro-C for 8051 Release 3.2
* c:\mc\cc51 7-seg -i h=c:\mc m=t
*/
#include c:\mc\8051io.h /* include i/o header file */
#include c:\mc\8051reg.h
extern register char cputick; // cputick was incremented every 10ms
register unsigned char flag1;
unsigned register char sec,digit,buffer[2];
register char key;
char convert[10] = {0x3F,0x0c,0x76,0x5e,0x4d,0x5b,0x7b,0x0e,0x7f,0x5f};
/* my LED's segment pin designation (differs from standard)
b
__
a|__| c
f| | d
--
e
*/
#define setValue 99
main()
{
flag1 = 0;
sec = setValue;
timeToBuffer();
serinit(9600); // set timer0 to be 16 bit counter
while(1){
while(cputick < 10)
scanLED();
// execute the following functions every 100ms
cputick = 0;
timeToBuffer();
keyexe();
countdown();
}
}
scanLED() /* scan 2-digit LED and 2-key switch, if key pressed key = 0-1
else key = -1 */
{
int i;
digit = 0x02; // scan code 00000010
key = -1;
for( i = 0; i < 2; i++) /* 2-DIGIT scanning */
{
P3 = ~digit; /* send complement[digit] */
P1 = ~buffer; /* send complement[segment] */
delay(1); /* delay 1ms */
P1 = 0xff; /* off LED */
if ((P3 & 0x10) == 0) /* if key pressed P3.4 became low */
key = i; /* save key position to key variable */
digit>>=1; /* next digit */
}
}
timeToBuffer() // converts binary data in sec to 7-segment pattern
{
buffer[0] = convert[sec%10];
buffer[1] = convert[sec/10];
}
countdown()
{
if ((flag1 & 0x02) != 0)
sec--;
if (sec == 0 )
flag1 &= ~0x02; // clear run bit
}
keyexe()
{
if (key != -1)
{
switch(key){
case (0): /* key position 0 */
reset(); /* service key 0 */
break;
case (1): /* key position 1 */
run(); /* service key 1 */
}
}
}
reset()
{
sec = setValue; // reload set value
timeToBuffer();
flag1 &= ~0x02; // stop counting down
}
run()
{
if (sec != 0)
flag1 |= 0x02; // start counting down
}
