About JTAG mux or bridge to enable multiple target FPGA connections

[caomxin]

Hi, recently I'm on a project to connect multiple Target FPGAs to a Microzed 7010 motherboard. I have successfully implemented One Single daughter board following "XAPP1251 (v1.0) April 30, 2015". However that implementation limit the JTAG signals to only PMOD JA and I want to do some multiplexing work. I have read JTAG SCAN BRIDGE and many other relevant materials but have no idea how to get it work.

My idea is to share TCK, TMS for JA, JB, JC etc and TDI for JA and TDO for the last PMOD that pinned together. Will that work? Thanks.

[adrianh-xlnx]

Have you considered creating a JTAG chain with your devices as shown below?

JA -> JB -> JC

If you create a chain you won't need a scan bridge and the Vivado tools should work with no problems; provided all the devices follow the ieee 1149.1a spec.

[adrianh-xlnx]

Sorry, for accidentally closing the thread.... pressed wrong button.

Here is one link that you can see on page 10 how the devices are wired up:

https://www.corelis.com/education/JTAG-Tutorial.pdf

Hope this helps.

[prshant-mehta]

@caomxin - Can we close this issue if @adrianh-xlnx's response answers your question?