DSPIC Oscillator/Timer Questions.

How does one calculate the period of interrupt requests? Let the internal clock be set to 10MHz. The period is 100ns. Since the clock is divided by 256 (prescaler reduces the clock 1:256) to form the timer clock, it follws that the the timer clock is 100*256=25600ns i.e. 25.6µs. At each 10000 clocks an interrupt is requestd, i.e. at each 256ms or approximately 4 times per second.

T = 10000*25.6µs = 256ms ~ ¼s.

Click to expand...

variaseng said:

I'm confused about what the internal clock here is. For example, I'm using a primary oscillator which is 8MHz. This is the Fosc, right? And Fcy = Fosc/4. But which is the internal clock that I should use for calculating the period of interrupt requests?

Thank you very much!

Click to expand...

9.2 Timer Prescaler
The input clock (FOSC/4 or external clock) to the 16-bit
Timer has a prescale option of 1:1, 1:8, 1:64 and 1:256,
selected by control bits TCKPS<1:0> (T1CON<5:4>).

Click to expand...

variaseng said:

And Fcy = Fosc/4.

Click to expand...