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: 
Visitor dmajoe
Visitor
3,158 Views
Registered: ‎10-12-2011

Powering of the MGTAVCC GTP tiles for JTAG use

Jump to solution

Hi!

I am designing a small test board to get started with the Virtex 5 LX50T.
The configuration guide says that:-
If Boundary-Scan is used as part of the product verification in the LXT or SXT, the analog
supply voltage pin MGTAVCC of all GTP_DUAL tiles must be powered.

Is it essential to have the MGTAVCC powered JUST FOR JTAG FLASHING ?

Basically I did not power these lines. And now I cannot get a device ID back from the JTAG.
So I am guessing its because I didnt power these lines.

In which case why doesnt everyone always power these lines... or do they?

 

Dennis

0 Kudos
1 Solution

Accepted Solutions
Xilinx Employee
Xilinx Employee
3,961 Views
Registered: ‎08-28-2007

Re: Powering of the MGTAVCC GTP tiles for JTAG use

Jump to solution

Dennis,

 

This should only affect boundary scan operations where you access the full scan chain such as EXTEST. The IDCODE will still ouput a good IDCODE if your JTAG chain is setup correctly. I assume by JTAG flashing you mean programming of the FPGA, that will also work in your scenario assuming the JTAG chain is setup correctly in other respects.

 

This sounds like you have some kind of layout/component/electrical/signal integrity issue on your JTAG lines and should be debugged as such. The MGTAVCC issue is not a possible root cause here.

 

-P

View solution in original post

0 Kudos
2 Replies
Xilinx Employee
Xilinx Employee
3,962 Views
Registered: ‎08-28-2007

Re: Powering of the MGTAVCC GTP tiles for JTAG use

Jump to solution

Dennis,

 

This should only affect boundary scan operations where you access the full scan chain such as EXTEST. The IDCODE will still ouput a good IDCODE if your JTAG chain is setup correctly. I assume by JTAG flashing you mean programming of the FPGA, that will also work in your scenario assuming the JTAG chain is setup correctly in other respects.

 

This sounds like you have some kind of layout/component/electrical/signal integrity issue on your JTAG lines and should be debugged as such. The MGTAVCC issue is not a possible root cause here.

 

-P

View solution in original post

0 Kudos
Visitor dmajoe
Visitor
3,147 Views
Registered: ‎10-12-2011

Re: Powering of the MGTAVCC GTP tiles for JTAG use

Jump to solution
MANY THANKS, I will check the JTAG lines. Dennis
0 Kudos