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Altera_Forum
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13 years ago

EP4CE15 powers on to user IO pins at HIGH and not HIGH-Z

Hello, I am experiencing some issues with an EP4CE15 at reset (and power on) setting its pins to HIGH (1.7 - 1.8V) instead of HIGH-Z. I very strongly believe that there is no short in the board,...
Altera_Forum's avatar
Altera_Forum
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13 years ago

Search the PDF for "pull-up", and you'll see:

p109: Figure 6-1 - the pull-up has a programmable switch.

p170: "The user I/O pins and dual-purpose I/O pins have weak pull-up resistors, which are always enabled (after POR) before and during configuration."

p457: Table 1–12. Internal Weak Pull-Up and Weak Pull-Down Resistor Values for Cyclone IV Devices, RPU = "Value of the I/O pin pull-up resistor

before and during configuration, as well as user mode if you enable the programmable pull-up resistor option."

So there is your answer.

Cheers,

Dave