Error: Can't access JTAG chain

[Altera_Forum]

When i try to program the FPGA cyclone III i get this error : 

error: can't access jtag chain error: operation failed. I am using a FPGA cyclone III .I would be able to program it a few months ago with no problem but now it suddenly gives me that error.Can anyone help??  ps. I am using the usb blaster.  please can somebody help me?

[Altera_Forum]

There can be a lot of reasons. Power supply, unconnected pin, missing pull-up... You can start with the JTAG chain debugger (described on pages 20-20 to 20-29 of the programmer datasheet (http://www.altera.com/literature/hb/qts/qts_qii53022.pdf)).

[Altera_Forum]

If you can't access the JTAG chain, the primary reason could be connection problem or no power detected on the JTAG chain. Please check your JTAG header pins (and possibly connections). You might have mistakenly misplaced them.

[Altera_Forum]

you can also check with your blaster. try changing it and configuring with new blaster. sometimes the buffer inside blaster damages which might cause this error.

[Altera_Forum]

the same problem is trouble me too，but when i check my quartusII 9.0, i haven't find JTAG debug tools under the tools menu。can anyone help me pls！

[Altera_Forum]

Tools > JTAG Debug tools was introduced later in 10.0

[Altera_Forum]

Zhang, in Quartus 9.1 the JTAG debugger is not under Tools; it is under Processing->JTAG Chain Debugger. This is the menu of the Programmer tool, not the main Quartus window. Hopefully it is there in 9.0 as well. 

 I am having the same problem with a custom PCB that I designed and built using a USB Blaster for JTAG communications with a Cyclone III. The design is based on a known-good design, but I have not been able to establish communications with the FPGA yet. Sadly there are many MANY things that can go wrong with such a complex system, resulting in loss of communications.

[Altera_Forum]

HI ,the same problem puzzled me now, and i don't know where the wrong is. The pcb is also a finished product,when i download the program by jtag, it gives the error "can't access the jtag chain" 

The 50MHZ crystal's output is between 1.2v-2.2v. Whether the source is right?

[Altera_Forum]

Even with no clock at all, the FPGA should respond on the JTAG connection. The problem is probably somewhere else that the crystal. Check the power supplies, ground connections, impedances on the JTAG lines, etc... Check also the JTAG signals with a scope, especially the clock that is often the source of JTAG problems. 

As for the voltage levels, you can check the input/outputs characteristics of your FPGA in the literature and see if you can use an I/O standard that is compatible with those voltage levels.

[Altera_Forum]

Hii here is my pcb 

 http://hiphotos.baidu.com/wswuda2007...5692457e8d.jpg (http://hiphotos.baidu.com/wswuda2007/pic/item/bfae41cbd9c13e5692457e8d.jpg) http://hiphotos.baidu.com/wswuda2007...4501e9288d.jpg (http://hiphotos.baidu.com/wswuda2007/pic/item/598f21c9b4e24f4501e9288d.jpg) http://hiphotos.baidu.com/wswuda2007...d7b2b7dc8d.jpg (http://hiphotos.baidu.com/wswuda2007/pic/item/e08f2341110f9bd7b2b7dc8d.jpg)   Is there need anyother connection?

[Altera_Forum]

--- Quote Start ---  When i try to program the FPGA cyclone III i get this error : error: can't access jtag chain error: operation failed. I am using a FPGA cyclone III .I would be able to program it a few months ago with no problem but now it suddenly gives me that error.Can anyone help??   ps. I am using the usb blaster.   please can somebody help me?  --- Quote End ---     http://hiphotos.baidu.com/wswuda2007/pic/item/bfae41cbd9c13e5692457e8d.jpg  http://hiphotos.baidu.com/wswuda2007/pic/item/598f21c9b4e24f4501e9288d.jpg  http://hiphotos.baidu.com/wswuda2007/pic/item/e08f2341110f9bd7b2b7dc8d.jpg

[Altera_Forum]

Turns out my main problem is that the FPGA isn't soldered to the board. Truely an epic fail. Will come back here and report after we get another board fabed.

[Altera_Forum]

wswuda2007: I can't see any image you post. 

Did you try and check the signals with a scope? hines1957: what package is it? was it glued on the board?

[Altera_Forum]

--- Quote Start ---  wswuda2007: I can't see any image you post. Did you try and check the signals with a scope? hines1957: what package is it? was it glued on the board?  --- Quote End ---     Sorry about that, I don't know how to put the images on the forum by easily giving the URL/. By the way,I've checked the CONFIG_DONE pin by scope ,but it has no change. Are there other pins do i need pay attention to?

[Altera_Forum]

Check the JTAG signals. Especially the clock, that must have clean edges.

[Altera_Forum]

--- Quote Start ---  Check the JTAG signals. Especially the clock, that must have clean edges.  --- Quote End ---      Bad news for me! The JTAG's TCK pin has no signal at all. When I connect the USB-BLASTER to the JTAG's ten pins, the TCK is always 3.3v,and without the USB-BLASTER,it is always 0v.   What's the real signal of the TCK as it should be? The TCK signal is given by the FPGA or the usb-blaster?

[Altera_Forum]

It should be a clock signal. Are you looking while you are doing a configuration?

[Altera_Forum]

TCK is driven by USB-Blaster but only while something is using it. A quartus_pgm will drive it continually but something like the Nios debugger or terminal will drive it in bursts if it is just polling for activity

[DevRuibin]

I can relate to your issue. I attempted to resolve it and it appears to be functioning properly now.

Below is my solution:

1. Follow the steps in the link. It works initially, but the problem resurfaces after a day.

2. It appears that the error message "Error: Can't access JTAG chain" was caused by a permission issue. In order to resolve the problem, I reinstalled Quartus (version 22) as the root user, and this successfully solved the issue.

3. It's a good idea for a regular user to launch the program, as it avoids the need to constantly switch users. To grant others the same permissions as the root user, I utilized the command `ruibin@E590:/media/ruibin/Data/01/2531/quartus/quartus/bin$ sudo chmod u+s *`.

4.If you come across this issue: Quartus displays an error message stating "error while loading shared libraries: libprotobuf.so.14: cannot open shared object file: No such file or directory." see: https://www.intel.com/content/www/us/en/support/programmable/articles/000093063.html 

I understand that launching the software as a root user may not be the best approach, but it seems like the most direct solution to my problem. If you have any other suggestions, please share them with me. Thank you! 

Also, I hope my response can be helpful to anyone else who is facing a similar issue.