Lattice Semiconductor Corporation

Ting Yew

Brad Sharpe-Geisler

Senani Gunaratna

Chan-Chi Jason Cheng

Qin Wei

Satwant Singh

Ann Wu

Chi Minh Nguyen

Ronald L Cline

Various techniques are provided to efficiently implement user designs in programmable logic devices (PLDs). In one example, a programmable logic device (PLD) includes a plurality of programmable logic blocks (PLBs) and at least first and second logic cells within at least one of the PLBs, where each logic cell includes a lookup table (LUT) and associated mode logic configured to receive a LUT output signal from the LUT. The associated mode logic is configured to use a single physical signal output to provide a logic cell output signal corresponding to a selected logic function operational mode, ripple arithmetic operational mode, or extended logic function operational mode for each logic cell.

Multiple mode device implementation for programmable logic devices

Various techniques are provided to efficiently implement user designs in programmable logic devices (PLDs). In one example, a programmable logic device (PLD) includes a plurality of programmable logic blocks (PLBs) and a plurality of logic cells within at least one of the PLBs, where each logic cell includes a four input lookup table (4-LUT) configured to provide a 4-LUT output signal to associated carry logic. Each logic cell is configurable according to at least two selectable operational modes including a logic function output mode and a ripple arithmetic output mode, and at least three of the 4-LUT inputs are interchangeable when a selected operational mode comprises the ripple arithmetic output mode.

Flexible ripple mode device implementation for programmable logic devices

Various techniques are provided to efficiently implement selective power gating of routing resource configuration memory bits for programmable logic devices (PLDs). In one example, a PLD includes a routing circuit configured to selectively route input nodes to an output node. The PLD further includes configuration memory cells configured to store configuration bit values to control the routing circuit. The PLD further includes a power circuit configured to power the configuration memory cells while storing the configuration bit values. The PLD further includes an enable bit memory cell configured to store an enable bit value to interrupt at least one connection of the power circuit to the configuration memory cells. The configuration memory cells are configured to provide, in response to an interruption of the connection, default configuration bit values to the routing circuit to prevent routing the input nodes to the output node. Additional systems and related methods are provided.

Selective power gating of routing resource configuration memory bits for programmable logic devices

A programmable logic is provided that uses only NMOS pass transistors to pass a true output signal to an internal true node and to pass a complement output signal to an internal complement node. The internal true and complement nodes are cross-coupled through PMOS transistors so that the discharge of one of the internal true and complement nodes switches on a corresponding one of the cross-coupled PMOS transistors to charge a remaining one of the internal true and complement nodes.

High speed complementary NMOS LUT logic

A control circuit is provided that enables a register to provide a synchronous initialization capability as well as an asynchronous capability despite the register having no asynchronous input.

Shared logic for multiple registers with asynchronous initialization

In one embodiment, a programmable logic device (PLD) with configuration memory includes at least one configuration memory cell and soft error detection (SED) logic for checking for errors in data stored by the configuration memory. The SED logic calculates a present data value for the configuration memory for comparison with a pre-calculated data value. A fuse within the PLD is configurable in a first logic state to enable the SED logic to read from the configuration memory cell in calculating the present data value and configurable in a second logic state to prevent the SED logic from reading from the configuration memory cell in calculating the present data value. The SED logic may be tested for correct operation by writing data representing a soft error into the configuration memory cell and enabling the SED logic to read from the configuration memory cell in calculating the present data value.

Testing of soft error detection logic for programmable logic devices

A programmable logic device, in accordance with one embodiment, includes a plurality of configuration memory cells, wherein at least one configuration memory cell is adapted to function as random access memory. Read/write circuitry writes to and reads from a corresponding first port of the configuration memory cells, including reading from the at least one configuration memory cell adapted to function as random access memory. Soft error detection logic checks for an error in data values stored by the plurality of configuration memory cells, including the at least one configuration memory cell adapted to function as random access memory. The soft error detection logic, for example, may thus be tested by changing a data value stored in the at least one configuration memory cell.

Soft error detection logic testing systems and methods

Systems and methods are disclosed herein to provide high fan-out signal routing. For example, in accordance with an embodiment of the present invention, a programmable logic device includes a plurality of logic blocks; an interconnect structure adapted to route signals among the logic blocks; and a secondary routing network adapted to route signals among the logic blocks. The secondary routing network may include a plurality of horizontal splines adapted to route signals within the programmable logic device; a plurality of vertical spline taps adapted to route signals within the programmable logic device; a plurality of common interface blocks adapted to route signals between the horizontal splines and the vertical spline taps; and a plurality of horizontal secondary branches adapted to route signals from the vertical spline taps to the logic blocks.

High fan-out signal routing systems and methods

In one embodiment, a programmable logic device is provided that includes a memory having memory cells, each memory cell operable to store either a configuration bit or a RAM bit; a masking circuit operable to mask a RAM bit by providing a masking value for the masked RAM bit; an error detection circuit operable to process the configuration bits during operation of the programmable logic device using an error detection algorithm, the error detection circuit calculating a signature that includes configuration bits and masking values; and a comparator operable to compare the signature calculated by the error detection circuit with a correct signature.

Growing community of inventors

San Jose, CA, United States of America

Ting Yew