humpy
Newbie level 2
how to create remote control fan regulator
Hi,IanP
I tried to find out the zero crossing point.I used a 0-18v transformer.I rectified it with bridge rectifier and i gave this rectified voltage to the base of BC547.Base resistor=10k,collector resister=4.7k.The collector pin is connected to the RB0 pin of pic16f876a.I treid to read the time interval between two zero crossing(it must be 10ms right?)using timer1 with out using any prescaler.But i am getting the timer value as 19937.Ie that much microsecond instead of 10 ms.So where is the problem?Is threr any thing wrong with the programe or design?.
Here is the program in HI-Tech for finding the time period.
I used 4Mhz crystal.
#include <pic.h>
unsigned char first,second;
unsigned short x;
__CONFIG(WDTDIS & XT & UNPROTECT & PWRTDIS & BORDIS & LVPDIS );
/*************************************************************/
static void interrupt isr()
{
if(INTF)
{
GIE=0;
if(first)
{
TMR1ON=1; //First zero crossing timer value=0
first=0;
}
else if(second)
{
TMR1ON=0; //second zero crossing,Read timer1 in to x
x=TMR1H;
x=x<<8;
x=(x| TMR1L);
first=1;;
TMR1H=0;
TMR1L=0;
x=0;
}
}
INTF=0;
GIE=1;
}
void main(void)
{
T1CON=0b00001000;
TMR1H=0;
TMR1L=0;
first=1;
second=1;
TRISB=0b00000001;
INTF=0;
INTEDG=0;
INTE=1;
GIE=1;
while(1)
{
PORTB=0; //Nothing to in while loop
}
}
IanP said:
Hi,IanP
I tried to find out the zero crossing point.I used a 0-18v transformer.I rectified it with bridge rectifier and i gave this rectified voltage to the base of BC547.Base resistor=10k,collector resister=4.7k.The collector pin is connected to the RB0 pin of pic16f876a.I treid to read the time interval between two zero crossing(it must be 10ms right?)using timer1 with out using any prescaler.But i am getting the timer value as 19937.Ie that much microsecond instead of 10 ms.So where is the problem?Is threr any thing wrong with the programe or design?.
Here is the program in HI-Tech for finding the time period.
I used 4Mhz crystal.
#include <pic.h>
unsigned char first,second;
unsigned short x;
__CONFIG(WDTDIS & XT & UNPROTECT & PWRTDIS & BORDIS & LVPDIS );
/*************************************************************/
static void interrupt isr()
{
if(INTF)
{
GIE=0;
if(first)
{
TMR1ON=1; //First zero crossing timer value=0
first=0;
}
else if(second)
{
TMR1ON=0; //second zero crossing,Read timer1 in to x
x=TMR1H;
x=x<<8;
x=(x| TMR1L);
first=1;;
TMR1H=0;
TMR1L=0;
x=0;
}
}
INTF=0;
GIE=1;
}
void main(void)
{
T1CON=0b00001000;
TMR1H=0;
TMR1L=0;
first=1;
second=1;
TRISB=0b00000001;
INTF=0;
INTEDG=0;
INTE=1;
GIE=1;
while(1)
{
PORTB=0; //Nothing to in while loop
}
}