Need help, timer1

ahmad · Joined: 09 Mar 2007 Posts: 6

I am using pic16f877a and set timer 1 ,I need to know each increment
in timer 1 what will be equal in us, please help me.
I am using pcm v4.024
#use delay(clock=4000000)
setup_timer_1(T1_INTERNAL | T1_DIV_BY_4);

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

Well, the way to figure this is take the main oscillator (Fosc) divide that by 4 (a hardware division), divide that by 4 (since you have that configured in your setup_timer_1() statement) and then divide that by 65536 (which equals the 16 bit register that counts the clocks) and you will have the frequency of Timer1's interrupt.

Fosc/4/4/65536.

You will get 3.8146972 interrupts each second which equals to be aproximately 262mS between each interrupt.

Clear as mud?

Ronald