Advanced Micro Devices Corporation

Lattice Semiconductor Corporation

Kapil Shankar

Om P Agrawal

Cyrus Y Tsui

Albert L Chan

Ju Shen

Michele Young

Fares N Mubarak

David Lee Rutledge

Arthur H Khu

Milton M Hood, Jr

Rudolf Usselmann

Thomas J Davies, Jr

Mark A Moran

A structure and a method provide a programmable logic device including a number of generic logic blocks and one or more application-specific block. Such application-specific block implements a specific function, such as a register file or a memory array. In one embodiment, the application specific block is programmable to be either one or more single-port memory array, a first-in-first-out (FIFO) memory, or a dual port memory array. In another embodiment, the application-specific block can be configured to be a register file, a number of counters, a number of timers, or a shift register. The application-specific block can be used in conjunction with programmable logic arrays for multiplexing input and output signals into and out of the application-specific block. Interconnectivity between the generic logic blocks and the application-specific blocks using a global routing resource integrates into a programmable logic device functions otherwise difficult to implement using only generic logic blocks.

Application specific modules in a programmable logic device

A non-volatile, in-system programmable integrated-circuit switch has horizontal conductive lines and vertical conductive lines. A programmable interconnect cell including a floating gate transistor is provided at each intersection of a horizontal line and a vertical line. Each line is connected to a pin through a programmable I/O cell which includes a floating gate transistor. Each I/O cell can be programmed to configure the corresponding pin as an input pin or as an inverting or non-inverting output pin. The I/O cell can also be programmed to tri-state the pin or to fix the pin at a high or low voltage level. Each input pin can be connected to more than one output pins. A TTL-to-CMOS translator in each I/O cell is provided in the output section of the cell to reduce the translator output load and make the load, and hence the speed and power consumption of the switch, less dependent on the switch programming.

Programmable integrated-circuit switch

A structure and a method to implement in-system programming (ISP) and boundary-scan testing in an integrated circuit using the same pins to control both functions. The SDI, SCLK, MODE and SDO connections required for in-system programming and the TDI, TCK, TMS and TDO connections required for boundary-scan testing are multiplexed such that they are provided from the same four pins. An in-system programming enable pin is used to control the multiplexing of these pins. In an alternative embodiment, both in-system programming and boundary-scan testing are performed using the same pins and the same state machine. The test logic architecture specified in IEEE Standard 1149.1-1990 is utilized. To implement the in-system programming instructions, the instruction register of Std. 1149.1-1990 is modified to include private instructions which perform the desired programming functions.

Multiplexed control pins for in-system programming and boundary scan

The disclosed structure and method route an input signal received at an input/output pin through multiple input/output cells to a routing resource. In one embodiment, each input/output cell can be programmed to provide either a combinatorial input signal or a registered input signal. Increased flexibility is achieved by routing the registered input signal or the combinatorial input signal of each cell to a routing resource via one or more I/O cells.

Input routing pool

An integrated circuit programmable sequencing element apparatus on a single chip is provided which includes a PROM including first signal receiving circuitry and second signal providing circuitry; at least one feedback signal providing circuitry responsive to at least one second signal for providing at least one feedback signal; at least one input signal providing circuitry for providing at least one input signal; at least one control signal providing circuitry for providing at least one control signal; at least one programmable sequencing element circuitry for receiving said at least one control signal and the at least one input signal and for providing at least one programmable sequencing element signal; and selection circuitry for selecting at least between the at least one programmable sequencing element signal and the at least one feedback signal and for providing at least one selected signal to the first signal receiving circuitry.

Integrated circuit programmable sequencing element apparatus

A macrocell is provided for use in logic circuits which is capable of being configured into any one of six different states so as to replicate an X-type output architecture, an L-type output architecture and a number of hybrid architectures which encompass features from one or both of these types.

Output logic macrocell

A structure for making programmable connections between the input and output terminals of individual logic blocks in a logic device is disclosed. In one embodiment, each output terminal is programmably connected to only one input terminal of each logic block. The same principle is followed in making connections between the input pins of the device and the input terminals of the logic blocks.

Programmable interconnect structure for logic blocks

An output logic macrocell ('OLMC') containing an exclusive OR gate is associated with the product terms and other outputs of a logic block such as a programmable logic array. The OLMC is capable of providing enhanced functions, including cascaded exclusive OR gates, function sharing, T and J-K flip-flop emulation, asynchronous clocking, and a reset selection. In addition, a logic block is used as the source of an asynchronous clock pulse and is connected to the global clock distribution system of a device such as a high density programmable logic device.

Output logic macrocell with enhanced functional capabilities

A device having a number of general registers each allocated an input/output port and a number of internal 'buried' state registers. A user-controlled signal permits observation of the contents of the buried state registers at an input/output port although these registers are not allocated an input/output port. Each register is connected to a logic circuit internal to the device by a dedicated feedback path so that all registers can be used to specify states in a state machine sequencer. A fuse-programmable XOR gate permits a user to control generation of signals at the ports by permitting enabling and disabling of an inverting output buffer. Asynchronous reset and synchronous preset of the registers is provided. In addition to the dedicated feedback paths, programmable feedback paths are provided. An output inverter can selectably be enabled from internal signals or from an externasl pin. The input/output circuit can be deployed in banks, each bank selectably receiving the same or a different clock. The registers can be preloaded via an internally-generated signal or from the external pins. In an alternative embodiment, a programmable AND array and a pair of programmable OR arrays, each serving one of the banks, provides a flexible programmable logic array device with observable buried states.

Programmable logic device with observability and preloadability for

A programmable logic device is disclosed which includes a programmable AND array, a plurality of logic circuits connected to groups of product term outputs from the AND array for performing a logical OR operation of the product term inputs and the programmable logic device includes programmable OR circuitry for selectively connecting one or more of the ORed groups of product terms to one or more outputs of the programmable logic device. The programmable OR circuit permits product term steering and sharing.

Programmable logic device providing product term sharing and steering to

Method and apparatus providing a programmable logic device which has a high level subroutine stack element and a random access memory suitable for control applications. The method utilizes high level constructs bearing a one-to-one relationship to the architecture of the apparatus so that the design of the controller is facilitated resulting in a rapidly-executed program which is easy to comprehend, verify and document. Subroutines are readily implemented by the controller by virtue of its last-in, first-out stack and a state counter which allow the contents of the counter to be 'pushed' onto the stack upon invocation of the subroutine and 'popped' from the stack upon return from the subroutine. Provision of the random access memory allows the controller to store information supplied from an external device, such as a central processing unit. The operation of the controller can be readily modified according to the control information stored in the memory by use of a high level language RAMREAD construct. The random access memory also provides scratch pad capability for the controller so that information written to a memory location, under control of a programmable OR array, can be used as a separate, independent counting and timing channel, in an exemplary application. The stack and/or the random access memory are suitable for inclusion in a controller of either a programmable logic array (PLA-), programmable array logic (PAL-), or a programmable read-only-memory (PROM-) based design.

Programmable logic device with subroutine stack and random access memory

A programmable array logic device including a programmable logic array, at least one register pair, a multiplexer coupled to the register pair so that they can share a common I/O pin, and an observability buffer for controlling the multiplexer. A dual clock buffer is provided so that registers within the register pair can be clocked singly when in a preload mode or together when in a logic or verification mode. When in the logic mode, either the output of a buried state register or a output register is observed at the I/O pin under the control of a product term generated by the logic array. When in the preload mode the register to be preloaded is selected by an externally provided preload select signal. In the verification mode, which typically follows a programming mode, individually selected product terms within the logic array can be observed by clocking them into the register pairs.

Programmable logic device with observability and preload circuitry for

A method for designing a control sequencer having a high level counter element and a programmable AND array suitable for control applications. The method utilizes high level constructs bearing a one-to-one relationship to the architecture of the apparatus so that the design of the controller is facilitated resulting in a rapidly-executed program which is easy to comprehend, verify and document. Moore and Mealy state machines are readily implemented by the controller by virtue of its programmable AND array and counter which allow the next-state and output to be based on the contents of the counter as well as any set of input signals. Conditional testing can be made entirely state dependent, partially-state dependent, or state-independent. Multiway branching is also readily implemented since the presence of the programmable AND array allows the user to specify a number of sets of input conditions, so that from a given state, as determined by the counter contents, each set of input condition gives rise to a transition to a specified next state. Instruction decoding for the controller is preformed in the programmable AND array, and thus can be specified by the designer in the high-level software method of the invention. Accordingly, instructions can be stored in the AND array in a logical form directly usable by the hardware. The counter is preferably of the Gray-code type so as to minimize instabilities in the output signals and to permit easy optimization of Boolean expressions involving the state of the device. Dedicated buried registers are provided as are dedicated feedback paths from the outpout registers, dedicated registers and counter to the AND array. Two separate OR arrays are provided, one generating output signals, the other generating control sequencing signals.

Method for designing a control sequencer

A programmable logic device has a high level counter element and a programmable AND array suitable for control applications. Moore and Mealy state machines are readily implemented by the controller by virtue of its programmable AND array and counter which allow the next-state and output to be based on the contents of the counter as well as any set of input signals. Conditional testing can be made entirely state dependent, partially-state dependent, or state-independent. Multiway branching is also readily implemented since the presence of the programmable AND array allows the user to specify a number of sets of input conditions, so that from a given state, as determined by the counter contents, each set of input condition gives rise to a transition to a specified next state. Instructions can be stored in the AND array in a logical form directly useable by the hardware. Dedicated buried registers are provided as are dedicated feedback paths from the output registers, dedicated registers and counter to the AND array. Two separate OR arrays are provided, one generating output signals, the other generating control sequencing signals.

Logic controller having programmable logic 'and' array using a

A logic circuit communicating to and from an input/output port in a variety of input modes and in a variety of output modes. The circuit may be configured to have a dedicated, registered, or latched input; and in the output mode to have a registered, combinatorial or latched output. A register/latch, in conjunction with a programmable input select multiplexer, can function as an input, output or buried register or as a transparent latch. A programmable clock select multiplexer selects between a clock/latch enable signal applied at an external pin or a product term generated internally. Clock polarity control is also provided. Asynchronous reset and preset of the register/latch is provided along with polarity control therefor. Dedicated and programmable feedback paths are provided. An output inverter can selectably be enabled from internal signals or from an external pin. The logic circuit can be deployed in banks, each bank electably receiving the same or a different clock. The register/latch can be preloaded via an internally-generated signal or from the external pins.

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San Jose, CA, United States of America

Kapil Shankar