the time isnt right?

[whung.john]

hi!
today i will be make a seccond time model in my program.
but i calculated follow as .i tested counter timer fast .i check really time.
my model have question.
have body can teach me .where is error ? tHK u

#include <16F877.h>
#use delay(clock=10000000)
#fuses NOWDT,HS,NOLVP,BROWNOUT
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#include <LCD>

#define CLK_74164 PIN_C3
#define D0_74164 PIN_C1 /
#define CLR_74164 PIN_C2

unsigned int j=0,sec1=0,min1=0;
const char a[]={0x80,0xeb,0x4c,0x49,0x2b,0x19,0x38,0x8b,0x08,0x0b,0xff};




void write_74164(BYTE eo) {
BYTE i;

for(i=1;i<=8;++i) { // Clock out bits from the eo array
if((((eo))&0x80)==0)
output_low(D0_74164);
else
output_high(D0_74164);
shift_left(&eo,1,0);
output_low(CLK_74164);
output_high(CLK_74164);
}
}

#int_timer0
void timer0_isr()
{
set_timer0(100);
j++;
if (j==1000)
{
sec1++;
j=0;
lcd_gotoxy(1,2);printf(lcd_putc,"\nnow sec:=%u",sec1);
if (sec1==60)
{ min1++;
sec1=0;
write_74164(a[min1]);
}
}
}

void init74164(void)
{
output_low(CLR_74164);
DELAY_MS(100);
output_high(CLR_74164);
output_low(CLR_74164); //clock l
output_high(CLR_74164);//clock h
delay_ms(100);
}


void main()
{
unsigned int i;



init74164();
lcd_init();

write_74164(0xf7);
delay_ms(1000);

i=0;
do
{
write_74164(a[i]);
lcd_gotoxy(1,1);printf(lcd_putc,"now number:=%u",i);
delay_ms(300);
i++;
}
while (i<11);
write_74164(a[10]);


setup_counters(rtcc_internal,rtcc_div_16);
enable_interrupts(int_timer0);
enable_interrupts(global);

while(1);
//output_low(CLR_74164);




}

[PCM programmer]

Read posts on Timer0 accuracy:

See Ttelmah's post:
http://www.ccsinfo.com/forum/viewtopic.php?t=18175

See Neutone's post at the end of this thread:
http://www.ccsinfo.com/forum/viewtopic.php?t=17915

[WHUNG.JOHN]

HI:PROGRAMMER SIR
i have read u suggest on post information.
and i find my program have some area that the same question.
i have modified finish.but i calculate timer0 counter still very fast .
and I have checked time still have question.
sir ,please direct error area.
i calcuate method follow as ;
because i use 10MZ clock,so i calcuate is => 1/10MZ/(4*16)=6.4us
i want to get a second. so i calcuate is => 1ms=1000us
1000us/6.4us=156 ticks and check calcuate 156*6.4us=998.4us
the 998.4us is very the same 1ms value number for my use .
i modified my program.please tell me my think where is bad.
my modified in here.follow as

#include <16F877.h>
#use delay(clock=10000000)
#fuses NOWDT,HS,NOLVP,BROWNOUT
#include <LCD>

#define CLK_74164 PIN_C3
#define D0_74164 PIN_C1
#define CLR_74164 PIN_C2

int j=0,sec1=0,min1=0;
const char a[]={0x80,0xeb,0x4c,0x49,0x2b,0x19,0x38,0x8b,0x08,0x0b,0xff};

#int_TIMER0
void TIMER0_isr(void)
{
set_timer0(100);
j++;
if (j==1000)
{
sec1++;
j=0;

}

}

void write_74164(BYTE eo)
{
BYTE i;

for(i=1;i<=8;++i) {
if((((eo))&0x80)==0)
output_low(D0_74164);
else
output_high(D0_74164);
shift_left(&eo,1,0);
output_low(CLK_74164);
output_high(CLK_74164);
}
}
void init74164(void)
{
output_low(CLR_74164);
DELAY_MS(100);
output_high(CLR_74164);
output_low(CLR_74164); //clock l
output_high(CLR_74164);//clock h
delay_ms(100);

}


void main()
{

init74164();
lcd_init();


setup_counters(RTCC_INTERNAL,RTCC_DIV_16);
enable_interrupts(INT_TIMER0);
enable_interrupts(global);
write_74164(0xf7);
while(1)
{

lcd_gotoxy(1,2);printf(lcd_putc,"\fnow sec:=%u",sec1);
delay_ms(100);

if (sec1==60)
{ min1++;
sec1=0;
write_74164(a[min1]);
}
}

}

[ckielstra]

[whung.john]

[ckielstra]

[whung.john]