California Institute of Technology

Alain J Martin

Rajit Manohar

Andrew M Lines

Uri V Cummings

Mika Nystroem

Wonjin Jang

Mika Nystr&ouml;m

Christopher D Moore

Mika Nystrom

Jonathan A Dama

Piyush Prakash

Brian Von Herzen

Catherine G Wong

Mika Nyström

Sean J Keller

Steven M Burns

Jose A Tierno

A random access memory (RAM) cell provides a control section and a storage section coupled to the storage section. The storage section includes complementary metal-oxide semiconductor (CMOS) transistors and the storage section is read by precharging the control section to a virtual drain voltage.

Ultra-low-power variation-tolerant radiation-hardened cache design

Single Event Upset (SEU, also referred to as soft error) tolerant arbiters, bare arbiters, and filters are disclosed. An arbiter provides a filter section, and a bare arbiter, coupled to the filter section. The bare arbiter includes a redundant first input and a redundant second input, and a redundant first output and a redundant second output. A pull-down transistor in the bare arbiter conditionally overpowers a corresponding pull-up transistor in the bare arbiter when a contention condition is present in the bare arbiter.

SEU tolerant arbiter

An asynchronous logic family of circuits which communicate on delay-insensitive flow-controlled channels with 4-phase handshakes and 1 of N encoding, compute output data directly from input data using domino logic, and use the state-holding ability of the domino logic to implement pipelining without additional latches.

Reshuffled communications processes in pipelined asynchronous circuits

Asynchronous nanoelectronic circuits that operate according to principles of quasi-delay insensitive design are described. Circuit or logic elements comprising n-type devices are fabricated in a first n-plane, p-type devices are fabricated in a p-plane, and connections are formed in a routing plane of a compute tile. A state-holding element comprising a selected one of a C-element, a precharge function-block, and a read-write register is described. The state-holding element can hold a value of an output of a logic element during a time when the output is disconnected from a reference voltage. Isochronic forks having an adversary path designed to make state transitions safe are explained.

Asynchronous nano-electronics

The invention provides circuits that are tolerant to soft errors, such as a single event upset (SEU). The circuits have a chain of permitted state changes. Redundant elements, including redundant literals and assignments, are designed and implemented in the circuit. The design is such that a disruption or change of state on a single element by an SEU will not change the state flow of a circuit or lead to impermissible state changes. In one embodiment, the invention is implemented in quasi-delay-insensitive (QDI) asynchronous circuits.

Method and apparatus for providing SEU-tolerant circuits

The present invention is a systematic and data-driven-decomposition (DDD) method and apparatus for use in VLSI synthesis. The invention decomposes a high level program circuit description into a collection of small and highly concurrent modules that can be implemented directly into transistor networks. This enables an automatic implementation of a decomposition process currently done by hand. Unlike prior art syntax-based decompositions, the method of the present invention examines data dependencies in the process' computation, and then attempts to eliminate unnecessary synchronization in the system. In one embodiment, the method comprises: a conversion to convert the input program into an intermediate Dynamic Single Assignment (DSA) form, a projection process to decompose the intermediate DSA into smaller concurrent processes, and a clustering process that optimally groups small concurrent processes to make up the final decomposition. Another embodiment is a decomposition, projection, and clustering tool implemented in computer program codes.

Method for the synthesis of VLSI systems based on data-driven decomposition

Systems and methods for mitigating the effects of soft errors in asynchronous digital circuits. Circuits are constructed using stages comprising doubled logic elements which are connected to c-elements that compare the output states of the double logic elements. The inputs of logic elements in a stage are inhibited from changing until the outputs of the c-elements of that stage are enabled. The c-elements inhibit the propagation of a soft error by halting the operation of the circuit until the temporary effects of the soft error pass.

Duplicated double checking production rule set for fault-tolerant electronics

The present invention is a class of circuits named asynchronous pulse logic (APL) circuit and designing methods for such circuits. APL replaces two of the four-phase handshakes in QDI circuits with pulses, thus breaking the timing dependencies that cause performance problems in QDI circuits. Since the pulse length in APL varies so little, it can be assumed constant. This assumption frees designers from needing to consider the effects of the inputs and outputs on the pulse length, which means timing properties can be verified locally. One embodiment of the present invention is a class of circuit design called the single-track-handshake-asynchronous-pulse-logic (STAPL), which serves as a new target for the compilation of CHP (Communication Hardware Process) programs. In one embodiment, a five-stage pulse generator is used to create a 10 transition count cycle circuit. Advantages of STAPL include a simplified solution to the charge-sharing problem and less loading from p-transistors.

Method and apparatus for an asynchronous pulse logic circuit

The present invention is a programming language method called Pipeline Language 1 (PL1) and its associated compiler system for generating logical circuit designs. The semantics allow the implementation to add more slack than exists in the specification, aiding the design of slack-elastic systems. In PL1, the value probe and peek are the most basic operations: receiving a value is done by first using the peek, and then acknowledging it as a separate action. Another embodiment is a PL1 compiler comprised of a technology-independent front-end module and a technology-dependent back-end module. It parses the input, converts it into BDD expressions, checks determinism conditions, generates BDD expressions for assignments and sends and converts the BDD expressions to unary representation. The back-end compiler module is technology-dependent, meaning that different back-end modules generate different circuit design types (e.g. QDI and STAPL). All back-end module embodiments perform logic simplification on input programs.

Method and system for compiling circuit designs

Unlike prior art synchronizers and asynchronous arbiters that produce glitches in their outputs, the present invention provides a failure-free synchronizer that can sample an arbitrary and unstable inputs while maintaining zero probability of system failure. In particular, the invention addresses the synchronization failure problem and the lack of a metastable state in prior art synchronizers. Prior attempts have shown that the conditions rex and rex (where re is the control input and x is the data input) cannot be arbitrated. To overcome this, embodiments of the present invention introduce explicit signals a and a to hold the values rex and rex, respectively. One embodiment is a fast synchronizer. It has four main components&mdash;an input integrator, an inverting component, a SEL component and an output filter. Another embodiment of the present invention is a safe synchronizer that meets the strictest QDI design requirements. Other embodiments use a standard arbiter and a killable arbiter for arbitration.

Method and apparatus for a failure-free synchronizer

An asynchronous processor having pipelined instruction fetching and execution to implement concurrent execution of instructions by two or more execution units. A writeback unit is connected to execution units and memory units to control information updates and to handle precise exception. A pipelined completion mechanism can be implemented to improve the throughput.

Pipelined asynchronous processing

An asynchronous circuit having a pipelined completion mechanism to achieve improved throughput.

Asynchronous circuits with pipelined completion process

Exception handling systems and techniques for handling exceptions and sequencing conflicts in an asynchronous processor. Two designated queues are used to respectively keep program counter values of instructions and the assignments of the execution units for executing the instructions according to the program order. An asynchronous circuit is coupled between the program counter unit and the write-back unit of the processor to provide asynchronous communications.

Growing community of inventors

Pasadena, CA, United States of America

Alain J Martin