If the board implements other configuration schemes (configuration device or processor based), the pull-up resistor is not required. In these scenarios, the configuration device or processor should hold the DATA input at a valid TTL logic level.
Article ID: 000086122 Content Type: Troubleshooting Last Reviewed: 09/11/2012
Do I need a pull-up resistor on the DATA configuration input signal of my Stratix, Stratix GX, or Cyclone device?
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Description A pull-up resistor to Vccio is recommended on the DATA input signal if the only configuration scheme implemented on the board is Passive Serial using a download cable (ByteBlasterMV, ByteBlaster II, or MasterBlaster). This pull-up resistor prevents the DATA input from floating when the cable is not connected to the board.