Altera Corporation

Gary Lai

Andy Louie Lee

Vaughn Betz

Ryan Fung

David Wolk Mendel

Lu Zhou

Bruce B Pedersen

Marcel A LeBlanc

Triet M Nguyen

Changsong Zhang

A programmable logic device includes logic blocks such as a logic array blocks (LAB) that can be configured as a random access memory (RAM) or as a lookup table (LUT). A mode flag is provided to indicate the mode of operation of configuration logic such as a configuration RAM (CRAM) used during partial reconfiguration of a logic block. An enable read flag is provided to indicate if values stored in the configuration logic are to be read out or a known state is to be read out during a data verification process. Thus, exclusion and inclusion of portions of a region of configuration logic from data verification and correction processes allow a region of configuration logic to store both a design state and a user defined state. Moreover, the region of configuration logic may be dynamically reconfigured from one state to another without causing verification errors.

Reconfigurable logic block

A programmable logic device includes logic blocks such as a logic array blocks (LAB) that can be configured as a random access memory (RAM) or as a lookup table (LUT). A mode flag is provided to indicate the mode of operation of configuration logic such as a configuration RAM (CRAM) used during partial reconfiguration of a logic block. If the mode flag indicates a design state, the configuration logic associated with the logic block is included in data verification and correction processes. If the mode flag indicates a user defined state, the configuration logic associated with the logic block is excluded from data verification and correction processes. Thus, exclusion and inclusion of portions of a region of configuration logic from data verification and correction processes allow a region of configuration logic to store both a design state and a user defined state without causing deleterious effects.

Reconfigurable logic block with user RAM

Clock switch-over circuits and methods provide clock signals to clock routing networks. According to one embodiment, a multiplexer selects between a first clock signal and a second clock signal in response to a switch select signal received from a control circuit. A storage circuit stores an enable signal in response to an output clock signal of the multiplexer. A logic circuit transmits the output clock signal of the multiplexer to a clock routing network in response to the enable signal from the storage circuit. At least one signal is transmitted from the clock switch-over circuit to the control circuit.

Clock switch-over circuits and methods

A programmable logic device (PLD) includes a signal distribution network, separate from the high-quality, low-skew clock distribution networks of the PLD, for distributing, from peripheral input/output regions of the PLD, clock-type signals. The signal distribution network includes a central periphery clock bus, located near a group of peripheral input/output regions, for conducting clock-type signals from those regions onto a clock spine of the PLD. The clock spine may be dedicated to the signal distribution network, or may be part of a high-quality, low-skew clock distribution network covering all or part of the PLD. The signal distribution network allows greater skew than such high-quality, low-skew clock distribution networks, but nevertheless is of higher quality, and allows less skew, than the general programmable interconnect and routing resources.

Periphery clock distribution network for a programmable logic device

Circuitry for providing an input data signal to other circuitry on an integrated circuit includes a course delay chain and a fine delay chain. These two delay chains are cascadable, if desired, to provide a very wide range of possible amounts of delay which can be finely graded by use of the fine delay chain.

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Palo Alto, CA, United States of America

Gary Lai