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UMall1's avatar
UMall1
Icon for Occasional Contributor rankOccasional Contributor
2 years ago
Solved

VCCIO

I am reading the Cyclone 10 GX datasheet and it seems the device is not capable of interacting with other devices that operate with 3.3V logic. It uses 3V logic.

I then come across the following Q&As:

Can I connect 3.3V devices to cyclone10GX? - Intel Community

Solved: Cyclone 10GX VCCIO 3.3V - Intel Community

Both categorically state that the IObanks can be connected to 3.3V. VCCIO = 3.3V and this allows the chip to interact with 3.3V devices. The main problem is that they cite Absolute maximum ratings as a source of this conclusion. Most people do not try to approach a device's Absolute max ratings. Is this now allowed in Cyclone 10GX.

Can the Cyclone 10GX interact with 3.3V devices? Can the VCCIO pins be connected to 3.3V? Why this confusion?

Is programming restricted to 1.8V? Is Bank 1 restricted to a specific VCCIO? Used to be 3.3V in Cyclone III devices.

Intel did incredibly well in sorting out Altera's confusing datasheets. Now there is confusing information in Intel documentation. Users expect better from INTEL.

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  • AqidAyman_Altera's avatar
    AqidAyman_Altera
    2 years ago

    In most cases, 3.3V I/O should be compatible with 3V I/O but it should not necessarily work all the system. I think it is safe to check the 3.3V device datasheet first before interacting with the Cyclone 10 GX. It should support as the DC input voltage maximum is 3.3V. In other words, it will support as long as the Vih, Voh, Vil, and Vol of both I/O standards are within the range of Cyclone 10 GX.





4 Replies

  • FvM's avatar
    FvM
    Icon for Super Contributor rankSuper Contributor
    2 years ago

    Hi,
    I don't agree that VCCIO needs to be raised to 3.3V to "interact" with 3.3 V devices. That's also well possible with VCCIO = 3.0 V.

    You still need to take care to keep the maximum input overshoot specification for signals driven by 3.3V logic. Appropriate termination schemes, e.g. source side series termination should be implemented for longer connections lines.

    • UMall1's avatar
      UMall1
      Icon for Occasional Contributor rankOccasional Contributor
      2 years ago

      How would the commanding of 3.3V logic proceed? Do all 3.3V systems have VOH smaller than 3V?

      Can you confirm that the VCCIO should remain 3V while interacting with 3.3V devices?

  • AqidAyman_Altera's avatar
    AqidAyman_Altera
    Icon for Regular Contributor rankRegular Contributor
    2 years ago

    In most cases, 3.3V I/O should be compatible with 3V I/O but it should not necessarily work all the system. I think it is safe to check the 3.3V device datasheet first before interacting with the Cyclone 10 GX. It should support as the DC input voltage maximum is 3.3V. In other words, it will support as long as the Vih, Voh, Vil, and Vol of both I/O standards are within the range of Cyclone 10 GX.





  • AqidAyman_Altera's avatar
    AqidAyman_Altera
    Icon for Regular Contributor rankRegular Contributor
    2 years ago

    I now transition this thread to community support. If you have a new question, Please login to ‘https://supporttickets.intel.com/s/?language=en_US’, view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you on your follow-up questions.