frequency counter help and pointers

[comwarrior]

Thanks jumper...

i had another look at the datasheet this morning (i see clearly now that the matrix code has stopped falling infront of my eyes)...
Timer1, has two clock sources, External via RC0/T1CKI or internal (Fosc/4)

Am i right in thinking Fosc/4 is the 'master' clock devided by 4? so, i'm using a 20MHz master clock, to the frequency for TMR1 will be 5MHz?

Again, please correct me if i'm wrong...
The prescaler for TMR1 if i set it to 1:8 does that mean the the clock frequency is devided by 8 resulting in a clock frequency of 625KHz?

I think the datasheet is actually starting to settle into my brain...

so, it's a 16bit timer, so it'll count upto 65535 pulses or for 0.104856 seconds...

So, if we assume a minimum of 4 power pulses to count (= 1 shaft rotation) therefor the minimum readable speed will be 600 RPM but after that, it should be accurite...

Am i about right?

thanks