VCCIO

[UMall1]

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.

[FvM]

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]

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_Intel · Accepted solution]

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_Intel]

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