Abstract: Various techniques for controlling use of configuration data for and/or a design implemented as user logic in a configurable PLD (programmable logic device) include programming the configurable PLD using configuration data provided by a secure device. The programmed configurable PLD includes user logic, a configurable device authorization code generator and a comparator. The user logic is immediately disabled after it is loaded into the configurable device. A configurable device authorization code is generated in the configurable device authorization code generator in the programmed configurable PLD and is sent to the comparator. A secure device authorization code is generated by a secure device authorization code generator and also is sent to the comparator. The comparator compares the two inputs and, if the configurable device authorization code and secure device authorization code are identical, the user logic is then enabled.

Abstract: A first pair of single-ended drivers, each having a respective output connected to a first line of a differential channel, are defined to work against each other with respect to driving a first signal on the first line of the differential channel. A second pair of single-ended drivers, each having a respective output connected to a second line of the differential channel, are defined to work against each other with respect to driving a second signal on the second line of the differential channel. Each of the first pair of single-ended drivers and each of the second pair of single-ended drivers is connected to receive a common input signal. A difference between the first signal on the first line of the differential channel and the second signal on the second line of the differential channel defines a differential signal that is representative of the common input signal.