cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
Highlighted
Visitor
Visitor
539 Views
Registered: ‎02-02-2019

Using Clock in Virtex 5 LX50T FPGA

I am using Virtex-5 LX50T Genesys 2 FPGA Board. On datasheet, it says " 500MHz+ clock speeds " . But on board, oscillator available is 100Mhz and I am using it. Can I use more speed upto 500MHz for a clock oscillator? 

Oscillator configurations for board are given in the picture attached 

 

Clock.JPG
0 Kudos
3 Replies
Highlighted
518 Views
Registered: ‎06-21-2017

Are you concerned about the input clock frequency or do you want to use a higher internal clock frequency?  The Virtex 5 has multiple DCMs and PLLs that will allow you to synthesize a wide range of frequencies.

0 Kudos
Highlighted
Visitor
Visitor
479 Views
Registered: ‎02-02-2019

I only know how to use this 100MHz clock which is from externall oscillator as shown in picture. Can I use any other higher frequency clock ? Whether any internal or other but I need to use higher frequency such as written in Manual of 500MHz ? I want you to know that I am new and in learning phase for VHDL and FPGA

Regards

0 Kudos
Highlighted
Advisor
Advisor
466 Views
Registered: ‎04-26-2015

@ammar_0697 The DCMs (built into the Virtex 5) can perform clock multiplication, so it can turn your 100MHz clock into a 500MHz one.

 

With that said, while the chips is technically capable of operating at 500MHz, it's probably not a good idea. At that speed you will need a register after every operation, and some operations will not be possible (eg. you cannot cascade block RAM at 500MHz, on any speed grade). Utilization of the chip will be limited, as any congestion is likely to result in a timing failure.

 

It would be much better to target 100 - 200MHz on the Virtex 5.

0 Kudos