Last time, the chieftain inadvertently left unused pins that should have required processing and turned on the power.
But the device was working as if nothing had happened...
I was curious, so I asked, "What is this phenomenon?" I asked a senior staff member,
He advised me to look at the Pin-Out of the Quartus® II Fitter Report.
Not knowing what he was talking about, I opened a report of a project that was synthesized, placed and routed on Altera's development software "Quartus® II". Then...
I found a pin that I had overlooked was set to "input with pull up"... even though the Pin Connection Guideline says to "connect to ground".
Did I set it up this way? I went to Device and Pin Options and opened the Unused Pins tab. Then...
Even though I had not configured anything myself, Quartus® II had set the default setting for unused user I/O to "set the unused I/O pins to Hi-Z state as input pins and enable the device's internal Pull-Up resistor, which means that the input pins are in Weak High state.
Thanks to this setting, it was safe to leave unused user I/O pins in the Open state (unconnected) on the board!
In fact, the state of unused user I/O can be selected according to the state of the board.
You can configure settings from Assignments < Device < Device and Pin Options < Unused Pins.
The following is a description of how each setting is processed on the board.
Thus, the new engineer's head is now tied by the skin. And Quartus® II taught him.
The optional pins can be used as user I/O when not in use, and can be set to open on the Quartus® II when not used as user I/O as well.
This is a default setting that can be inadvertently overlooked.
Cheers to the kindness of Quartus® II!
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