What is the resistance of the bus-hold/keeper or pull-up termination circuitry for the CoolRunner-II ?
The effective resistance of the termination circuitry varies with VCCIO and temperature.
At VCCIO = 1.8V, the effective resistance is typically 100kOhm.
As VCCIO increases, the effective resistance decreases. Typical for VCCIO = 3.3V is 42kOhm.
The minimum resistance value presented by the termination circuitry is 20kOhm.
The resistance is less with colder temperatures. For example, with VCCIO = 1.8V and temperature = -40C, the effective resistance is 50kOhm, and with a temperature of 125C the resistance is 111kOhm.
For information on enabling or disabling the termination circuitry, see (Xilinx Answer 14318).