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: 
Highlighted
Observer geerard
Observer
7,320 Views
Registered: ‎07-25-2016

KC705 JTAG chain and FMC HPC connector

When I connect a 3rd party board (TI ADC12D1600RFRB) to the FMC HPC connector, I loose connection with the JTAG chain and I am unable to program the FPGA. According to me, it is the JTAG bypass switch which is opened by HPC pin H2, which is connected to ground on the daughter board. The JTAG pins on the HPC connector (D29-D31) of the daughter board are not connected, neither bypassed.

 

Is there a way to bypass this JTAG switch (U76) manually on the KC705?

Tags (3)
0 Kudos
6 Replies
Adventurer
Adventurer
7,300 Views
Registered: ‎02-24-2012

Re: KC705 JTAG chain and FMC HPC connector

@geerard

 

Hi,

 

dirty hack is to short pins 1 and 2 of the U76.

 

Best Regards,

 

Stephan

0 Kudos
Observer geerard
Observer
7,294 Views
Registered: ‎07-25-2016

Re: KC705 JTAG chain and FMC HPC connector

In the mean time, I've also found a topic on the TI E2E forum describing this issue on a similar board, confirming your proposal.

https://e2e.ti.com/support/data_converters/high_speed_data_converters/f/68/p/394209/1393474

0 Kudos
Moderator
Moderator
7,287 Views
Registered: ‎07-23-2015

Re: KC705 JTAG chain and FMC HPC connector

@geerard Or one way would be to pull R9.1 pin to Ground. Whichever works for you. 

 

Btw is U76 broken on your KC705?

 

Is it still under warranty? If not, then the above suggested methods would be the only hack which you would need to revert back when you remove the FMC daughter card. 

- Giri
--------------------------------------------------------------------------------------------------------------------
There's no such thing as a stupid question. Feel free to ask but do a quick search to make sure it ain't already answered.
Keep conversing, give Kudos and Accept Solution when you get one.
-----------------------------------------------------------------------------------------------------------------------
0 Kudos
Observer geerard
Observer
7,281 Views
Registered: ‎07-25-2016

Re: KC705 JTAG chain and FMC HPC connector

@gnarahar,

 

The U76 is not broken, and pulling R9.1 pin to ground would permanently open the JTAG chain, regardless of whether or not an FMC board is connected. This is thus not an option. Shorting this R9 is also not an option, since the pin on the ADC board is direcly connected to the ground plane, which would create very large currents.

0 Kudos
Moderator
Moderator
7,278 Views
Registered: ‎07-23-2015

Re: KC705 JTAG chain and FMC HPC connector

@geerard My bad. I missed the point in your original post about JTAG pins on the FMC daughter card not being connected. 

 

Yeah, R9.1 doesn't help. Shorting Pins 1 & 2 of U76 is the only way to go. 

- Giri
--------------------------------------------------------------------------------------------------------------------
There's no such thing as a stupid question. Feel free to ask but do a quick search to make sure it ain't already answered.
Keep conversing, give Kudos and Accept Solution when you get one.
-----------------------------------------------------------------------------------------------------------------------
0 Kudos
Xilinx Employee
Xilinx Employee
7,095 Views
Registered: ‎08-01-2012

Re: KC705 JTAG chain and FMC HPC connector

As it mentioned in previous post TDI and TDO short is one option.

 

Before that please check the JTAG chain connections carefully. Especially TDO-TDI-TDO-TDI loop,  There could be some extra loops for JTAG connections. Also make sure TCK and TMS connected to all devices including third party device.

 

Is third party device is as per JTAG IEE1149.1 standard? 

________________________________________________

Please mark this post as an "Accept as solution" in case if it helped to resolve your query. So that it will help to other forum users to directly refer to the answer.

Give kudos to this post in case if you think the information is useful and reply oriented.

0 Kudos