frequency counter

[SocMatt]

Hi

I need a frequency counter and had success using the example code ex_freqc.c, however now i need the frequency counter to work over two channels.
Can i reproduce the code for two channels or is it specific to that input pin of the PIC.

Any help would be most appreciated

Matt

 

[falleafd]

Post the code upto here, because some of us dont use CCS C, so if you have the code, it's easier for people to help you.

 

[SocMatt]

Here is the code:

#include <16F876.h>
#fuses HS, NOPROTECT, NOPUT, NOWDT, NOBROWNOUT
#use delay(clock=20000000) //one instruction=0.2us
#use rs232(baud=57600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#bit t1_overflow=0x0A.4

// #bit t1_overflow=0xF9E.0 (PIC18, Reminder)

void main() {
int cycles8, cycles;
int32 freq;
long freqc_high;
long freqc_low;

while (TRUE) {
cycles8=0;
cycles=0;
freqc_high=0;
t1_overflow=0;
set_timer1(0);
setup_timer_1(T1_EXTERNAL|T1_DIV_BY_1);
/* ___ wait one second ___ */
while (cycles!=0xFF) { //true=3, false=4
cycles8=0; //1 cycle
//start inner loop
while (cycles8!=0xFF) { //true=3, false=4
if (t1_overflow)//true=2,false=3 //----|
{t1_overflow=0;freqc_high++;}//6 cycles // |
else // |-- 8 cycles
{delay_cycles(5);} //----|
delay_cycles(62); //x
cycles8++; //1
///2 cycles to jump to top
//math: end inner loop
//math: total inner loop=((3+8+x+1+2)*255 + 4)*255
//math: if x=62.87781 then inner loops takes 5mil instructions
//math: if x=62 then inner loop takes 4942920, have to fill 57080 cycles
}
delay_cycles(216); //y
cycles++; ///1 cycle
///2 cylces to jump to top
//math: outer=(3+1+y+1+2)*255+4=57080
//math: y=(57080-4)/255)-(3+1+0+0+1+2)
//math: if y=216.827450980392156862745098039216 then outer loop cylces is 57080
//math: if y=216 then outer loop cycles is off by 211 cycles. z=211
}
delay_cycles(211); //z
/* ___ end waiting 1 second ___ */
setup_timer_1(T1_DISABLED); //turn of counter to prevent corruption while grabbing value
if (t1_overflow) //check one last time for overflow
freqc_high++;
freqc_low=get_timer1(); //get timer1 value as the least sign. 16bits of freq counter
freq=make32(freqc_high,freqc_low); //use new make32 function to join lsb and msb
printf("%LU Hz\r\n",freq); //and print frequency

}
}


Cheers