Abstract: A method of minimizing power consumption in an integrated device is disclosed. The method comprises providing a plurality of circuit blocks having circuits for performing logic functions, wherein each circuit block consumes power in a static state; coupling one of a plurality of operating voltages to each circuit block of the plurality of circuit blocks; enabling a reduction of power consumed by a first set of circuit blocks by way of a first power reduction signal; and enabling a reduction of power consumed by a second set of circuit blocks by way of a second power reduction signal. A circuit for minimizing power consumption in a device is also disclosed.

Abstract: An integrated circuit system (120) includes a memory array (122) storing a configuration data set to configure an integrated circuit. The integrated circuit (121) includes a configuration memory (128) and a configuration controller state machine (126). The configuration controller state machine operates so as to read a read-check signature at a read-check address of the memory array (122) and to compare the read-check signature with a standard signature stored in the integrated circuit (121). If the read-check signature passes the comparison, the configuration controller state machine (126) loads the configuration data set from the memory array to the configuration memory (128) of the integrated circuit.

Abstract: A method of employing memory cells of an integrated circuit is disclosed. The method comprises steps of storing configuration data in a plurality of memory cells of a memory of the integrated circuit; selecting unused memory cells of the memory of the integrated circuit for use as a scratchpad memory; providing access to the unused memory cells of the integrated circuit; and enabling use of the unused memory cell of the integrated circuit in a user mode as scratchpad memory. According to one embodiment of the invention, a plurality of input/output ports of the integrated circuit is coupled to a plurality of JTAG inputs coupled to the plurality of unused memory cells. A programmable logic device having memory cells for storing data, and a circuit employing a programmable logic device, are also disclosed.

Abstract: Method and apparatus for testing input/output circuits of an integrated circuit are described. An integrated circuit includes input/output circuits having input/output pads. The input/output pads are capable of being coupled together to a tester channel. The input/output circuits each are configurable via configuration circuitry to be in either a first mode or a second mode responsive to a select circuit of the configuration circuitry coupled to receive a first input for the first mode and a second input for the second mode. The select circuit is controlled responsive to a control select signal common to all or a portion of the select circuits of each of the input/output circuits.

Abstract: A method of minimizing power consumption in an integrated device is disclosed. The method comprises providing a plurality of circuit blocks having circuits for performing logic functions, wherein each circuit block consumes power in a static state; coupling one of a plurality of operating voltages to each circuit block of the plurality of circuit blocks; enabling a reduction of power consumed by a first set of circuit blocks by way of a first power reduction signal; and enabling a reduction of power consumed by a second set of circuit blocks by way of a second power reduction signal. A circuit for minimizing power consumption in a device is also disclosed.

Abstract: A method of employing memory cells of an integrated circuit is disclosed. The method comprises steps of storing configuration data in a plurality of memory cells of a memory of the integrated circuit; selecting unused memory cells of the memory of the integrated circuit for use as a scratchpad memory; providing access to the unused memory cells of the integrated circuit; and enabling use of the unused memory cell of the integrated circuit in a user mode as scratchpad memory. According to one embodiment of the invention, a plurality of input/output ports of the integrated circuit is coupled to a plurality of JTAG inputs coupled to the plurality of unused memory cells. A programmable logic device having memory cells for storing data, and a circuit employing a programmable logic device, are also disclosed.

Abstract: Methods and structures for design security in configurable devices are described. In some embodiments, a configurable device may be placed in an unsecured mode allowing for access to configuration data and other diagnostic functions during development and production phases. Once the device is finalized, it may be placed in a secure mode that disables a configuration path and enables a bypass path, thereby securing the configuration data. In some embodiments, the configurable device may be a programmable logic device, such as a complex programmable logic device.

Abstract: Area-efficient power-up and enable control circuits useful in PLD interconnection arrays. A control circuit can include a driver circuit, first and second pull-ups, and first and second pull-downs. The driver circuit has an output terminal coupled to a control circuit output terminal. The first and second pull-ups are coupled in series between the control circuit output terminal and power high. The first pull-up has a gate terminal coupled to an enable terminal. The second pull-up has a gate terminal coupled to a pull-up control terminal. The first and second pull-downs are coupled in parallel between the control circuit output terminal and ground. The first pull-down has a gate terminal coupled to the enable terminal. The second pull-down has a gate terminal coupled to a pull-down control terminal. In other embodiments, the first and second pull-ups are coupled in parallel, and the first and second pull-downs are coupled in series.

Abstract: A technique and circuit implementation are described for automatically detecting a change in a power supply voltage and selectively reconfiguring a circuit for optimized performance at the changed voltage. One application of particular interest is an auto-detect level shifter. The auto-detect level shifter can be used in an output driver and can be automatically enabled if it is needed to optimize performance for various I/O standards, including those that operate at different voltages.

Abstract: An integrated clock doubler and polarity control circuit are described. The circuit provides high speed response between an input signal and an output signal, achieving clock doubling by passing the input signal through a delay circuit and using the output of the delay circuit to select between two paths for inverting or not inverting the input signal to produce the output signal. In one embodiment, the inverting path is a CMOS inverter with input terminal receiving the input signal, output terminal providing the output signal, and power terminals controlled by the delay circuit.

Abstract: Area-efficient power-up and enable control circuits useful in PLD interconnection arrays. A control circuit can include a driver circuit, first and second pull-ups, and first and second pull-downs. The driver circuit has an output terminal coupled to a control circuit output terminal. The first and second pull-ups are coupled in series between the control circuit output terminal and power high. The first pull-up has a gate terminal coupled to an enable terminal. The second pull-up has a gate terminal coupled to a pull-up control terminal. The first and second pull-downs are coupled in parallel between the control circuit output terminal and ground. The first pull-down has a gate terminal coupled to the enable terminal. The second pull-down has a gate terminal coupled to a pull-down control terminal. In other embodiments, the first and second pull-ups are coupled in parallel, and the first and second pull-downs are coupled in series.

Abstract: A programmable logic device includes a function block to generate a power control signal that is distributed on a rail to selectively power down various components on the device. The rail is coupled to an observation pin to allow for external observation of the power control signal. The power control signal is also provided as a feed forward signal to an input signal blocking circuit, which selectively enables or disables the device input pins in response to the feed forward signal. The feed forward signal is not accessible from the observation pin, and therefore cannot be externally altered from the observation pin.

Abstract: An integrated clock doubler and polarity control circuit are described. The circuit provides high speed response between an input signal and an output signal, achieving clock doubling by passing the input signal through a delay circuit and using the output of the delay circuit to select between two paths for inverting or not inverting the input signal to produce the output signal. In one embodiment, the inverting path is a CMOS inverter with input terminal receiving the input signal, output terminal providing the output signal, and power terminals controlled by the delay circuit.

Abstract: A low-voltage output circuit configurably providing a bus-hold function and a weak pull-up function, while having only transitory leakage current through the circuit regardless of the voltage level on the pad. Thus, the output circuit can be used in low-voltage devices that interface with higher-voltage devices without paying the penalty of increased leakage current. One embodiment of the invention includes a circuit output node coupled to a configurable weak pull-up circuit, a configurable bus hold circuit, and a configurable leakage prevention circuit. The configurable circuits are controlled by configuration signals that determine which circuits are active. One embodiment is implemented as a portion of a programmable logic device (PLD), and the configuration signals are programmed into configuration memory cells as part of the configuration of the PLD.

Abstract: An integrated clock doubler and polarity control circuit are described. The circuit provides high speed response between an input signal and an output signal, achieving clock doubling by passing the input signal through a delay circuit and using the output of the delay circuit to select between two paths for inverting or not inverting the input signal to produce the output signal. In one embodiment, the inverting path is a CMOS inverter with input terminal receiving the input signal, output terminal providing the output signal, and power terminals controlled by the delay circuit.

Abstract: A programmable logic device (PLD) performs a self-test blank check erase verify operation on memory elements of the PLD to verify that they are erased prior to programming. An enhanced reference voltage source is provided to reliably generate a reference source voltage at a predetermined voltage level regardless of variations in the on-chip power supply voltage and temperature variations. The reference voltage source includes a first resistor connected between the on-chip voltage source and an output node, a second resistor connected to the output node, and a reference voltage adjustment circuit connected between the second resistor and ground. The reference voltage adjustment circuit is programmable to selectively connect the output node to ground through one or more resistive elements in response to input signals such that the output node is maintained at the predetermined reference voltage.