Can I leave HSWAP_EN unconnected if it is not used? Does HSWAP_EN have an internal pull-up prior to configuration?
HSWAP_EN has an internal pull-up prior to configuration. The strength of the pull-up is defined by Irpu in the device data sheet. For Spartan-3 this internal pull-up is strong enough to hold the pin High so no external resistor is needed. For Spartan-3E the internal pull-up is weaker so extra precaution can be taken by adding a stronger external pull-up to ensure a logic level High.
For more information on hot swapping Spartan-3 devices, see (Xilinx Answer 19777).
The DC and Switching Characteristic datasheet for Spartan-3 can be found at:
The DC and Switching Characteristic datasheet for Spartan-3E can be found at: