I have a question on a FPGA P/N EP1C20F324C7 I want the signal DATADIR to go to gnd. Do I connect it directly to ground or do I Contact it to ground through a resister, and if I use a resistor what value should it be?

[SreekumarR_G_Intel]

Cyclone FPGA IO can directly connect the pin to the Ground. But it is recommended to connect through resistor to protect from accidentally driving a pin as output. 

Please refer the below link for Cyclone handbook Table 4–3. Cyclone Device DC Operating Conditions ,

https://media.digikey.com/pdf/Data%20Sheets/Altera%20PDFs/Cyclone_FPGA_Family.pdf

There is also feature in Intel FPGA called , " Bus hold " You can refer in section in handbook.External pull-up or pull-down resistor is not necessary to hold a signal level when the bus is tri-stated. 

Note: The bus-hold circuitry is only active after configuration,whereas external resistor are active before and during configuration.

[SreekumarR_G_Intel]

Hello there , if you don t have further question on this topic , Can you please close the thread ?