Clock frequency

P

Thread Starter

patheticz

Joined Nov 3, 2009

28

Nov 3, 2009

• #1

How do i generate a clock frequency for a FPGA chip?
beside using a crystal

 

Papabravo

Joined Feb 24, 2006

22,083

Nov 3, 2009

• #2

I dunno -- What are your requirements for frequency, stability, accuracy et cetra. How can we answer your questions if you fail to supply any information?

 

beenthere

Joined Apr 20, 2004

15,819

Nov 3, 2009

• #3

Get a TTL or CMOS oscillator. Mouser and Digi-Key carry a wide selection.

Here is a link to a manufacturer so you can get an idea of the frequencies available - most are standard -http://www.well.com/~oe/OscFreqs.html

 

Papabravo

Joined Feb 24, 2006

22,083

Nov 3, 2009

• #4

You can also use a PLL, divider, and a VFO

 

P

Thread Starter

patheticz

Joined Nov 3, 2009

28

Nov 3, 2009

• #5

Sorry for the lack of information
First of all, the query arose because i am designing an embedded controller for a a power switching module that is supposed to be able to function at swtiching freq of at least 10kHz.
then i was looking through the specification sheet and realized that the Virtex 5 and virtex 6 FPGA can operate at 400MHz -1000MHz.
Therefore, i was not sure what methods can i use to generate signal for the clock if i am going to use either of the FPGA

 

Papabravo

Joined Feb 24, 2006

22,083

Nov 4, 2009

• #6

Those frequencies are maximums. There is absolutely nothing that says you have to operate at such frequencies. In any case the way you genrate 10 kHz from a crystal or other type of oscillator is to pick a convenient frequency and divide it down.

 

auri_z

Joined Feb 5, 2009

8

Nov 4, 2009

• #7

it depend your requiments,if you need stability use crystal if not oscilator from some R and C can make it..

 

P

Thread Starter

patheticz

Joined Nov 3, 2009

28

Nov 4, 2009

• #8

Papabravo said:

Those frequencies are maximums. There is absolutely nothing that says you have to operate at such frequencies. In any case the way you genrate 10 kHz from a crystal or other type of oscillator is to pick a convenient frequency and divide it down.

Click to expand...

i am a bit confused here.
does that mean by having an oscillator of 10kHz, i can also generate frequency that is higher than that?

 

Nanophotonics

Joined Apr 2, 2009

383

Nov 4, 2009

• #9

patheticz said:

by having an oscillator of 10kHz, i can also generate frequency that is higher than that?

Click to expand...

No, you always generate a lower clock frequency from a higher one.

 

beenthere

Joined Apr 20, 2004

15,819

Nov 4, 2009

• #10

I gave you a bad link. Try Maxim - http://para.maxim-ic.com/en/search.mvp?fam=osc_mod&980=XO&tree=clkgen