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Altera_Forum's avatar
Altera_Forum
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16 years ago

Cyclone III and JTAG programming problem

Hi everybody,

I have a problem concerning programming my Cyclone III device. I have a original USB Blaster cable which for sure works fine. The problem is that when I try to use it, Quartus responds that device is not found.

I use it on a board that was designed by me so maybe there are some mistakes, but I don't know what else to check. I've already checked all the connections, voltages etc, they seem to be fine.

Any ideas?

6 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Apart from incorrect connected JTAG interface, the most popular design faults with Cyclone III are:

    - missing GND connection of exposed pad with EQFP144 package

    - missing 2.5V supply for VCCA

    Basically, the JTAG interface is kept in reset, until VCCINT and VCCA reach a minimum level. Also the exposed pad's GND connection is required for operation.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Thanks. I think exposed pad is an issue, since it is the first time I hear of it!

    I'm a complete beginner...
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    It's only present with 144 pin package, not with 240 pin or any BGA version.

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Oh yes, I know, and this is the case. I'll try to fix it tomorrow, keep your fingers crossed ;)

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Depending on the board layout, you may be able to create a connection to the exposed pad by carefully milling a hole into to the assembled board. Forum members already have reported a succesful repair.

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    It works! Board looks quite weird with such a hole, but this is not that important... Thanks a lot!