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Altera_Forum's avatar
Altera_Forum
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14 years ago

voltage of 3.3v not achieved even though programmed

Hello,

I am using altera cyclone 3 FPGA for one of my applications. I have programmed the output pins to be 3.3v LVCMOS output(from the PIN Planner). However when I check the output in the scope, I find that the output is always 2.5V. Can someone please tell me how to program the output pins so that the desired output of 3.3V is obtained.

Thanking you

Yours faithfully

Ranjan Banerjee

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    Are the VCCIO pins for those IO banks connected to 3V3 on your board?

    If you're getting 2V5 out then I suspect that your VCCIO pins are actually connected to 2V5 and not 3V3.

    Mark.
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    Hallo,

    you could also check the *.pin file. Here you can verify that all informations from pin-planner are transferred right.

    Of course only if VCCIO is 3,3V, like wolforth said already.

    Greets
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    Hello,

    My pins are in IO bank 1 and 2. Can you please tell me how I see the VCCIO pins in these banks and find out to what voltage values they are tied to. I am a bit new to this so I am not very sure how to find it. Help would be greatly appreciated.

    Regards,

    Ranjan
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    --- Quote Start ---

    Can you please tell me how I see the VCCIO pins in these banks?

    --- Quote End ---

    You would want to consult the board schematics or in case of a development kit, the users manual.