Hiển thị số '1234' trên LED 7 đoạn - PIC6F887

[chimcon]

EM VIET CHUONG TRINH DEM SAN PHAM DUNG CCS KHONG BIET SAO MA
BAO LOI QUA TROI. MONG CAC BAN GIUP DO\
// Author : Tran Van Duy
// Date : 06/04/09
// Hardware: PIC16F887
//************************************************** ***************************
#include <16F887.h>
#fuses NOWDT,PUT,HS,NOPROTECT
#use delay(clock=4000000)
#use fast_io(b)

int16 a, dem;
int8 i, nghin, tram, chuc, dvi;

void hex_bcd()
{
nghin=a/1000;
a=a%1000;
tram=a/100;
a=a%100;
chuc=a/10;
dvi=a%10;
}
void hienthi()
{
i=0;
while(i<100)
{
output_b(dvi|0xE0); //don vi so 4
output_d(dvi|0xE0); //don vi so 4
delay_ms(2);
output_b(chuc|0xD0);
output_d(chuc|0xD0);
delay_ms(2);
output_b(tram|0xB0);
output_d(tram|0xB0);
delay_ms(2);
output_b(nghin|0x70);
output_d(nghin|0x70);
delay_ms(2);
i++;
}

}
void main()
{
set_tris_b(0x00);
set_tris_d(0x00);
dem=0;
while(1)
{
dem=dem+1;
if(dem==10000)
{
dem=0;
}
a=dem;
hex_bcd();
hienthi();
}
}