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SHard2's avatar
SHard2
Icon for Occasional Contributor rankOccasional Contributor
5 years ago
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Cyclone V nCEO pin , what VCCIO when used as IO pin

Hi From the documentation I am not clear what VCCIO standard the nCEO pin uses when configured as a general purpose IO pin. For example, I have a Cyclone V where VCCIO5A and VCCIO5B are connected...
  • AminT_Intel's avatar
    AminT_Intel
    5 years ago

    Hello Simon,

    The operating voltage for the configuration input pin is independent of the I/O banks power supply,
    VCCIO, during configuration. You may refer on page 246 of Cyclone V Device Handbook from this link: https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/cyclone-v/cv_5v2.pdf

    The nCEO pin will comply with Table 15 from page 19 of that Cyclone V Device Datasheet when it is configured as general purpose I/O pin. Thus, the Vih value will depends on the I/O standard you set.

    You are safe to put 3.3V of Vih to nCEO if you set 3.0-V LVTTL as I/O standard as situation you previously mentioned because the value of Vih can go up to 3.6V in that particular I/O standard.

    Hope this clarifies.

SHard2's avatar
SHard2
Icon for Occasional Contributor rankOccasional Contributor
5 years ago

Hi and thank you for getting back to me.

For final clarification, as I may have inadvertently confused things...

If the nCEO pin is configured as general purpose IO it will comply to its bank VCCIO which is 3V3.

I can therefore safely feed a signal with a Vih of 3V3 into the nCEO pin.

Best regards

Simon

AminT_Intel's avatar
AminT_Intel
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hello Simon,

The operating voltage for the configuration input pin is independent of the I/O banks power supply,
VCCIO, during configuration. You may refer on page 246 of Cyclone V Device Handbook from this link: https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/cyclone-v/cv_5v2.pdf

The nCEO pin will comply with Table 15 from page 19 of that Cyclone V Device Datasheet when it is configured as general purpose I/O pin. Thus, the Vih value will depends on the I/O standard you set.

You are safe to put 3.3V of Vih to nCEO if you set 3.0-V LVTTL as I/O standard as situation you previously mentioned because the value of Vih can go up to 3.6V in that particular I/O standard.

Hope this clarifies.