UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Explorer
Explorer
977 Views
Registered: ‎06-09-2018

ila probe effect functionality of my design

Hi everybody 

 

in my design i have an ila core that has some probes. if net that connect to probe no.7 is for example net no. 12 design work correct. but if net no. 13 connect to this probe design don't work correctly.

 

what is the problem?

0 Kudos
11 Replies
Scholar drjohnsmith
Scholar
962 Views
Registered: ‎07-09-2009

Re: ila probe effect functionality of my design

its broken is all we can say from this.

 

a lot more info needed ,

 

device and tools

  what are u doing

     what do you mean by broken, 

 

what do you mean by the numbers 

 

a look at your code ?

 

0 Kudos
Explorer
Explorer
951 Views
Registered: ‎06-09-2018

Re: ila probe effect functionality of my design

device and tools : 

artix 7/50t/-2

vivado 2017.4

what are u doing :

write to fifo and read from it 

what do you mean by the numbers :

net no. 12 or 13 means 2 different nets in my design. in detail my fifo is common clk and if i connect fifo clk to one ila probes, output of fifo that i see in ila is ok if this net(fifo clk) not conneted to one ila probes output of fifo isn't correct.

0 Kudos
Scholar drjohnsmith
Scholar
937 Views
Registered: ‎07-09-2009

Re: ila probe effect functionality of my design

sounds like a timing problem to the ILA,

    

have you tried putting some registers in the front of the ILA ?

     what frequency you cocking the fifo at ?

 

just check you have constant clocks into the fifo ?

 

a bit more detail would be of use,

 

The ILA, is routed, so it does affect the layout / timing, 

      but provided you have timing constraints in place and correct it works great.

 

 

 

one other thing, 

   does it simulate ok ?

 

 

0 Kudos
Explorer
Explorer
925 Views
Registered: ‎06-09-2018

Re: ila probe effect functionality of my design

what do you mean : "have you tried putting some registers in the front of the ILA ?"

 

fifo read and write frequency is 256 kHz

 

0 Kudos
Scholar drjohnsmith
Scholar
920 Views
Registered: ‎07-09-2009

Re: ila probe effect functionality of my design

KHz is very slow, that should not be a problem,  !!

   out of interest , how do you generate such a slow clock ?

        I'd normally be clocking the fifo faster, but putting a lower frequency enable into it.

 

what clock do you put into the ILA ?

 

re registers and the ILA ?

 

when you make the ILA, you have option to add pre registers, 

     if your clocking fast, it makes meeting timing easier for the tools.

 

 

0 Kudos
Explorer
Explorer
893 Views
Registered: ‎06-09-2018

Re: ila probe effect functionality of my design

if i clocked my fifo in this frequency Will there be a problem?

how do you generate such a slow clock ?

with a counter that counts faster clock period and generates slow clk.

what clock do you put into the ILA ? 

2.048 MHz

what do you mean : re registers and the ILA ?

0 Kudos
Scholar drjohnsmith
Scholar
865 Views
Registered: ‎07-09-2009

Re: ila probe effect functionality of my design

dont use gated clocks into fifos 

they need constant clock into them 

 

use your slow clock as the fifo enable 

 

re registers in front of the ILA ,

 

when you made the ILA , there is an option to add pre registers, 

 

   normally at 0, but if u had a fast clock, setting this to say 2 can improve layout / timing.

 

 

I don't feel thats its the ILA thats causing the problems here,

 

have you simulated ?

 

 

 

 

 

 

0 Kudos
Explorer
Explorer
812 Views
Registered: ‎06-09-2018

Re: ila probe effect functionality of my design

@drjohnsmith

if i use gated clk to fifo, what problems will happen?

 

if i connect slow clk to fifo enable, many false data will be written to fifo, this is not true(below image)?

 

"I don't feel thats its the ILA thats causing the problems here"

 

but i see like this problem in some other design (but rarely)

Untitled.png
0 Kudos
Scholar drjohnsmith
Scholar
809 Views
Registered: ‎07-09-2009

Re: ila probe effect functionality of my design

Generaly

 

Fifos need a constant clock into them,

   they have interesting clock crossing / synchronization circuits in them 

       

What I'd normally do is :

generate an enable pulse, one clock high , when I want data written to the fifo.

   This would be at the same frequency as you slow clock, but only active when you have data to go into the fifo.

         and clock the fifos at a constant clock,

 

Asics use  lots of clocks, and gated clocks , but Fifo's tend not to in the main.

 

Can we see you code ?

   this sort of problem tend to be due to other problems in the code.

        

You don't seem to want to answer my question as to have you simulated ?

    does that mean you have not ?

 

 

 

 

0 Kudos
Explorer
Explorer
536 Views
Registered: ‎06-09-2018

Re: ila probe effect functionality of my design

if i connect slow clk to fifo enable, many false data will be written to fifo, this is not true(below image)?

 

You don't seem to want to answer my question as to have you simulated ?

    does that mean you have not ?

:) , NO simulation is OK.

 

indeed i changed my code and a constant clk connected to fifo and problem has been fixed but because rarely i see this problem, in time i ask it...

Untitled.png
0 Kudos
Scholar drjohnsmith
Scholar
528 Views
Registered: ‎07-09-2009

Re: ila probe effect functionality of my design

Thats great news,  constant clock is what the fifo's need,

 

Great to hear about simulation working, thats always a good start.

 

Just make the enable to the fifo's one clock wide for the data you want

 

You seem less than confident about the results. Can we see your code, there might be some other pointers we can give you to get rid of your worries.

    

 

0 Kudos