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Altera_Forum
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16 years ago

Stratix III JTAG Failure

Hi All,

I have problem on Stratix III device on my Custom development board.

Device: Stratix III - EP3SL340

Download cable : Altera USB Blaster

We have provided two configuration option to configure the FPGA (JTAG & Passive serial).

Only one device is connected with the JTAG interface.

We are frequently using JTAG & USB blaster interface to validate our designs. so far It was working nicely.

Suddenly the quartus Tool is not able to detect the device from the JTAG chain.

I just went through the JTAG troble shooter, It gives the information of possible failure in the JTAG interface signal,

Also I have noticed that TDI pin is almost shorting to GND.

It shows 2 Ohm between TDI to GND.

Whereas the other working board it was around 150 to 200 ohm.

This is the second board I am facing the same issue.

Is it the problem with the Stratix III device JTAG interface.

Can anyone help me to findout the root cause for this trouble.

Best Regards,

Kalidoss

22 Replies

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  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Prototype assembly with leaded solder is O.K., except for BGA parts. But as said, the present TCK failure is most likely not related to this topic.

    Regarding debug options, you can detect if the short is at the FPGA side of the TCK net. If this is the case, it won't matter much, if it's inside the FPGA or e.g. a solder short. You have to desolder the part anyway to eliminate the short.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    It just might be that the USB Blaster is toast.

    I have seen this happen quite a few times.

    As a word of caution, please make sure that you disconnect the JTAG connector from the target baord before shutting down the power to the Host computer (Desktop or Laptop) as I have seen this 'back biasing' can kill the USB Blaster.

    Try another cable if you have one or if you are supported by an FAE< see if you can borrow one for a 1/2 hour to do some tests.

    Let us know how this goes.

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  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    I aslo met the similar problem, the JTAG can work normal several days ago, but now it can't work, I checked the net of the JTAG connector, found the TCK net is about 80 Ohms to GND.

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    I have similar problem too. My on-board JTAG doesn't work anymore after working for several months. I have cyclone II

    i found the tck net is about 35 ohms to gnd. In both directions.

    When power is supplied, I get 3.28V on TCK pin, I didn't notice over comsumption.

    I can still configure with Active Serial Programming. I notice that I have no progress bar but programming is succesfull.

    But I can't programm flash by Nios II.
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    One thing to check is the JTAG power supply. Is it suppose to be 3.3V or 2.5V for Cyclone II? Supplying the wrong voltage can damage the JTAG port and the device as well after seeming to work initially. Also when you ohm out the JTAG pins, they may appear to be shorted to GND. If this is the case, the only soln is to replace the FPGA.

    --- Quote Start ---

    I have similar problem too. My on-board JTAG doesn't work anymore after working for several months. I have cyclone II

    i found the tck net is about 35 ohms to gnd. In both directions.

    When power is supplied, I get 3.28V on TCK pin, I didn't notice over comsumption.

    I can still configure with Active Serial Programming. I notice that I have no progress bar but programming is succesfull.

    But I can't programm flash by Nios II.

    --- Quote End ---

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    Actually I just fixed a shorted TDO pin to ground by applying 3.8V to it. The pin went from 40 ohm to ground to over 200 ohm and now JTAG works again.

    I don't know why it failed, the board has been working fine for weeks. Today JTAG just stopped working. I guess a protection diode blew out and shorted. I just burned it open!
  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    Altera recommands to supply power on the board before plug USB Blaster in.

    TDO is an output pin : depends of technology (open-drain, TTL...) ohming it is not significant.

    JTAG problems seems to grow up last months on Cyclone II, Cyclone III, Stratix III
  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    ohming it may not be significant, but it was the problem and it fixed it.

  • Altera_Forum's avatar
    Altera_Forum
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    13 years ago

    No the board wasn't powered. I applied this voltage on just that jtag pin.