Article ID: 000085785 Content Type: Troubleshooting Last Reviewed: 09/11/2012

When is the weak pull-up resistor enabled during power up for Cyclone III and Cyclone IV devices?

Environment

BUILT IN - ARTICLE INTRO SECOND COMPONENT
Description

The weak pull-up resistor is enabled for Cyclone®, Cyclone II, Cyclone III and  Cyclone IV devices, after the device exits Power On Reset (POR) as indicated by the nSTATUS pin going high. The user I/O pins are tri-stated during power-up and during POR.  Thus if VCCIO is powered before VCC and other POR monitored supplies, the I/O pins will be tri-stated without the weak pull-up resistor enabled.

Related Products

This article applies to 5 products

Cyclone® II FPGA
Cyclone® FPGAs
Cyclone® III FPGAs
Cyclone® IV FPGAs
Cyclone® IV GX FPGA

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