[General question about using an external JTAG adapter on Digilent boards]

On 8/15/2023 at 8:35 PM, JColvin said:

Hi @Michael Fischer,

Yes, you may use an external JTAG programmer via J8 alongside the on-board USB-JTAG port J10, though I am not certain why you would want to do this as the JTAG chain will not allow two simultaneous connections to the same FPGA. Additionally, the Xilinx Hardware Device Manager is usually quite aggressive about maintaining access to all of the JTAG connections it can detect. In general I would also recommend not deliberately attempting to produce a drive conflict on a system, but that's neither here nor there.

Otherwise there are buffers and pull resistors on the JTAG lines between the on-board FTDI chip and the FPGA, though Digilent has chosen not to share this page of the schematic for any of our products.

Let me know if you have any questions.

Thanks,
JColvin

Hi JColvin,

So the on-board FTDI design will not drive if using the JTAG port on J8?

Or is a specific configuration needed for this to function?

 

One reason would be to use another debugger than what Eclipse/Vitis offers. That could be j-link and Ozone, a Lauterbach solution, or simply an external svf player to communicate with an FPGA core alongside the design once it has booted from SD.

 

Br Michael

[General question about using an external JTAG adapter on Digilent boards]

On 8/15/2023 at 11:14 PM, Michael Fischer said:

Hello @JColvin,

>though I am not certain why you would want to do this as the JTAG chain will not allow two simultaneous connections to the same FPGA.
I will not use both simultaneously. I want to connect a J-Link to the additional JTAG connector and test if the "xvcd-jlink" is working with
my Digilent boards too. The power will supply by the USB-JTAG, and the JTAG functionality will be used from the J-Link.

You can find more about the xvcd-jlink project here at GitHub:
https://github.com/playduck/xvcd-jlink

Best regards,
Michael

Hi @Michael Fischer,

I am looking for the same answer for my Zybo Z7 in order to attach a 3rd party debugger using xvcd.

Did you get this solved?

Another way I was looking for is to use JP3 and switch into separate chains but I have not traced this solution yet.

Br Michael

[Serial Wire Debug(SWD) and JTAG analyzer]

On 1/12/2022 at 3:19 PM, attila said:

Hi @yogeshL

The latest version adds JTAG support:

 

Hi Attila,

I just received my AD2 yesterday and am positively surprised on the possibilities of this device. I have worked in testing for many years (decades) specifically on IEEE 1149 (JTAG) and immediately started looking for jtag/swd support of on the device. 

I found this post, and see that it went in beta in January 2018, but the official release I find is a version 3.18.1 more than 4 years after the beta. Will there be a release or will I have to go for beta versions?

SVF file support would also be great as this could help in configuring FPGAs and the use SWD for MCU programming so the device serve even more purposes on top of all the awesome stuff it already does.

EDIT: Ah, nope it is the date you joined and not the date of the beta I was looking at ;o)

/Mike