Timer1 - frequency measurement

[aratti]

Visit the given link, schematic and code available.


http://digilander.libero.it/alfred73/eprojects.htm#1300 Mhz Frequencymeter with prescale

Al.

[Bruce]

I've read that, but i don't totally understand it

Which part are you having trouble with? I'll be happy to explain it.

thats why i wanted some help in getting started, i no timer1 would do what i need, but i don't no how to control timer1

T1CON on the 16F870 only has 6-bits that control the timer. Let me know what you don't understand that's in the data sheet, and I'll do my best to explain it. It would help if you tried a few code examples, and indicated which part you're having trouble with.

[-Dan-]

Which part are you having trouble with? I'll be happy to explain it.



T1CON on the 16F870 only has 6-bits that control the timer. Let me know what you don't understand that's in the data sheet, and I'll do my best to explain it. It would help if you tried a few code examples, and indicated which part you're having trouble with.

I don't understand how i work out, what the maximum frequency timer1 could capture from that data

[Bruce]

The datasheet shows T1CKI High Time min is 30nS for asynch mode with a prescaler of 1:1.

T1CKI Low Time is 30nS. And T1CKI minimum Input Period is 60nS.

So 1/60nS = the max input clock frequency it could handle. With your max freq at 200MHz
divided by 64, you should be well below the max clock input limit.

Look for AN592. Microchip shows an example using an old PIC1C5x with Timer0 that counts
up to 50MHz.

[-Dan-]

The datasheet shows T1CKI High Time min is 30nS for asynch mode with a prescaler of 1:1.

T1CKI Low Time is 30nS. And T1CKI minimum Input Period is 60nS.

So 1/60nS = the max input clock frequency it could handle. With your max freq at 200MHz
divided by 64, you should be well below the max clock input limit.

Look for AN592. Microchip shows an example using an old PIC1C5x with Timer0that counts
up to 50MHz.

Is there any examples written in picbasic pro, that you know of.