Abstract: In one embodiment, a programmable logic device includes a memory and an input/output (I/O) interface adapted to enter a variable response mode responsive to an assertion of a control signal. The I/O interface is operable in the variable response mode to respond to a read command from an external device by retrieving data from the memory and to shift dummy data to the external device until an internal data ready signal is asserted.

Abstract: Various techniques are provided to flexibly update data fields stored in multi-bit registers. In one example, a method of updating a control register within an integrated circuit includes storing a plurality of initial bit values in the control register within the integrated circuit. The method also includes receiving a data set comprising one or more corrective bit values and one or more non-corrective bit values. The method also includes performing a logic operation on the received data set and the initial bit values to provide updated bit values. The method also includes replacing the initial bit values with the updated bit values in the control register.

Abstract: In one embodiment, a programmable logic device such as an FPGA includes a programmable fabric adapted to operate normally and in a sleep mode, and a general purpose input/output port (I/O). The I/O port is adapted to function in conventional fashion during normal operation of the programmable fabric and as a wakeup control port during the sleep mode.

Abstract: A programmable logic device (PLD) is disclosed that includes a non-volatile memory; a shadow register; and a data shift register (DSR) configurable to receive control information from an external programming tool, wherein the DSR is configured to shift the control information into the shadow register if the PLD is in a first programming mode, the PLD being configurable to operate in the first programming mode using the control information stored in the shadow register without the control information being stored in the non-volatile memory.

Abstract: In one embodiment of the invention, an integrated circuit such as a programmable logic device includes volatile memory, nonvolatile memory, and a data shift register for reading data from the nonvolatile memory and for reading data from and writing data to the volatile memory. A built in self test (BIST) circuit is operable to test the nonvolatile memory without the data shift register reading data from the nonvolatile memory. The BIST circuit may include a finite state machine for performing at least one of the following tests on the nonvolatile memory: bulk erase, bulk program; margin bulk program; and/or margin bulk erase. A memory controller responsive to the finite state machine is operable to write data to and read data from the nonvolatile memory during testing of the nonvolatile memory.

Abstract: Various techniques are provided for determining interface characteristics of external devices. In one example, a method of configuring a programmable logic device (PLD) with configuration data stored in one or more external memory devices includes reading by the PLD an interface setup command in a bitstream from an external memory device through a configuration port of the PLD while operating the configuration port in accordance with a first set of interface characteristics. The method also includes adjusting by the PLD the configuration port to operate in accordance with a second set of interface characteristics identified by the interface setup command. The method also includes reading by the PLD configuration data in the bitstream from the external memory device through the configuration port while operating the configuration port in accordance with the second set of interface characteristics. The method also includes programming a configuration memory of the PLD with the configuration data.

Abstract: Various techniques are described to test memory arrays of a programmable logic device (PLD). In one example, a PLD includes a first memory array. The PLD also includes a plurality of sense amplifiers adapted to read a plurality of data values stored by the first memory array and provide a plurality of data signals corresponding to the data values. The PLD further includes a test circuit adapted to test the first memory array. The test circuit is coupled with the sense amplifiers and adapted to compare the data signals with a test signal to provide a pass/fail signal. In addition, the PLD includes a second memory array. The PLD also includes a data shift register adapted to test the second memory array.