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If its an all 5V system, then why would you suggest you are using VCCIO = 3.3V? :)
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I wasn't :-) That's why it probably came across as confusing...
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I'm not sure that anything really changes in the I/O cells based on these selections. I recall that selecting between standards gives you more current drive options in some of the newer devices, but I don't recall the FLEX10Ks as having a lot of flexibility. It may be that these settings are more "you telling the tool about the PCB" rather than the tool using those settings to set a bit in the configuration bit stream.
Either way, the I/Os are 5V tolerant, so you can try both. Generate a toggling signal and look at it with a scope for each setting.
Cheers,
Dave
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Yeah, either of the settings work which is somewhat puzzling. Right now I've been wrestling with some issues on my own PCB where I'm seeing some erratic behavior. Been poking around with a logic probe but looks like I need to bring out my scope..
-Mux
Honored Contributor
