Abstract: A circuit for transmitting signals in an integrated circuit device is described. The circuit comprises a first die; a second die stacked on the first die; and a buffer transmitting data between the first die and the second die; wherein a first inverter of the buffer is on the first die, and a second inverter of the buffer is on the second die. A method of transmitting signals in an integrated circuit device is also described.

Abstract: A netlist of a circuit design includes an interface portion and a main portion. The interface portion is decomposed into multiple levels. Each level specifies connections between a respective first set of circuit elements and a respective second set of circuit elements. The second set of circuit elements in each level, except a last level, includes the first set of circuit elements in a next level. The first set of circuit elements identified in a first level of the multiple levels have fixed locations. The second set of circuit elements in the multiple levels is placed-and-routed. The placing-and-routing of the second set of circuit elements in one level is completed before commencing placing-and-routing of the second set of circuit elements in the next level. The main portion is placed-and-routed after placing-and-routing the second set of circuit elements in the multiple levels.

Abstract: A circuit block within an integrated circuit includes a multiplexor (225, 625) configured to pass either a first signal or a second signal, wherein the first signal is independent of the second signal. The circuit block further includes a first flip-flop (210, 610) configured to receive an output of the multiplexor and a second flip-flop (215, 615) configured to receive the second signal. In a first mode of operation, the multiplexor passes the first signal to the first flip-flop. Further, the first flip flop and the second flip-flop operate independently of one another. In a second mode of operation, the multiplexor passes the second signal to the first flip-flop. Further, the first flip-flop and the second flip-flop both receive the second signal.

Abstract: A circuit includes a complimentary metal-oxide semiconductor (CMOS) storage element implemented within a p-type substrate and an n-well implemented within the p-type substrate that is independent of the storage element. The n-well and the storage element are separated by a minimum distance in which the p-type substrate includes no n-well.

Abstract: A method and apparatus to test the inter-die interface between two or more semiconductor die in die stacking applications, where a mismatch exists between the number of input and output pads on a base die and the number of input and output pads on a stacked die. In a first embodiment, a number of through-die vias (TDVs) may be used to implement inter-die signal paths using standard or flexible design rules to maintain statistical TDV yield despite the lack of continuity verification of the inter-die signals paths. In alternate embodiments, programmable multiplexers may be utilized to share one or more inter-die connections between the base die and the one or more stacked die so as to facilitate testing and normal operation of each inter-die connection. In other embodiments, spare TDVs are utilized only during test operations, so as to accommodate the mismatch.

Abstract: A programmable integrated circuit (IC) with mirrored interconnect structure. The IC includes a plurality of arrangements, which are horizontally arranged. Each arrangement includes a first logic column, an interconnect column, and a second logic column. Each interconnect column includes programmable interconnect blocks (148), and each of the first and second logic columns includes programmable logic blocks. Each programmable interconnect block provides a plurality of first input and output ports on a first side and a plurality of second input and output ports on a second side. The first ports and the first side of each of the programmable interconnect blocks physically mirror the second ports and the second side of the programmable interconnect block. The ports of the programmable interconnect blocks are coupled to the ports of the programmable logic blocks in the first and second logic columns.

Abstract: A programmable integrated circuit (IC) with mirrored interconnect structure. The IC includes a plurality of arrangements, which are horizontally arranged. Each arrangement includes a first logic column, an interconnect column, and a second logic column. Each interconnect column includes programmable interconnect blocks (148), and each of the first and second logic columns includes programmable logic blocks. Each programmable interconnect block provides a plurality of first input and output ports on a first side and a plurality of second input and output ports on a second side. The first ports and the first side of each of the programmable interconnect blocks physically mirror the second ports and the second side of the programmable interconnect block. The ports of the programmable interconnect blocks are coupled to the ports of the programmable logic blocks in the first and second logic columns.

Abstract: A method of modeling two IC dies using the same software model, although the two dies include physical differences. A first programmable logic device (PLD) die includes first and second portions, and is encoded to render the first portion operational and the second portion non-operational. At a boundary between the two portions, interconnect lines traversing the boundary include a first section in the first portion and a second section in the second portion. The second PLD die includes the first portion of the first PLD die, while omitting the second portion. The interconnect lines extending to the edge of the second die are coupled together in pairs. A software model for both die includes a termination model that omits the pair coupling, adds an RC load compensating for the omitted connection, and (for bidirectional interconnect lines) flags one interconnect line in each pair as being invalid for use by routing software.

Abstract: Methods of initializing an integrated circuit (IC) in which the routing structures have data lines and handshake circuitry are provided. A node of each of the data lines is driven to a predetermined value, and the handshake circuit is disabled by disabling an acknowledge path within the handshake circuitry, e.g., by forcing all acknowledge signals in the acknowledge path to signal an acknowledgement of received data. The disablement causes the predetermined value to propagate throughout the data lines. The handshake circuitry is then enabled by enabling the acknowledge path, which releases the data lines to assume values determined by operation of the IC. When the IC is a programmable IC, configuration values may be programmed into the IC after disabling the acknowledge path and before enabling the handshake circuitry. When the handshake circuitry is enabled, the data lines assume initial values determined by the programmed configuration values.

Abstract: Structures and methods of avoiding hold time violations in a design implemented in a PLD. In a programmable device, the delay of a signal path varies, e.g., depending on the separation between the source and destination of the signal. An optional delay element is provided between a programmable interconnect structure and a destination logic element having a clock skew relative to the source. The optional delay element is programmed by the implementation software to introduce a delay on the signal path when necessary to meet the hold time requirements for the destination logic element. The optional delay is designed to be large enough to overcome hold-time violations even for the largest possible clock skew and the smallest possible signal delay. When no hold time violation occurs, the optional delay element is configured to bypass the additional delay, to avoid imposing a large setup requirement on the signal.

Abstract: A method of modeling two IC dies using the same software model, although the two dies include physical differences. A first programmable logic device (PLD) die includes first and second portions, and is encoded to render the first portion operational and the second portion non-operational. At a boundary between the two portions, interconnect lines traversing the boundary include a first section in the first portion and a second section in the second portion. The second PLD die includes the first portion of the first PLD die, while omitting the second portion. The interconnect lines extending to the edge of the second die are coupled together in pairs. A software model for both die includes a termination model that omits the pair coupling, adds an RC load compensating for the omitted connection, and (for bidirectional interconnect lines) flags one interconnect line in each pair as being invalid for use by routing software.

Abstract: Interconnect driver circuits that can be used in the interconnect structures of dynamic integrated circuits (ICs) such as dynamic programmable logic devices (PLDs). An exemplary IC includes two or more logic circuits, and two or more self-resetting interconnect driver circuits coupled between the logic circuits. Each self-resetting interconnect driver circuit includes a multiplexer circuit driving a buffer circuit. In a first state, the buffer circuit drives a first value onto the output terminal of the buffer circuit. In a second state, the buffer circuit first drives a second value onto the output terminal of the buffer circuit and then returns to the first state. Several different circuits are described in detail.

Abstract: Structures and methods of avoiding hold time violations in a design implemented in a PLD. In a programmable device, the delay of a signal path varies, e.g., depending on the separation between the source and destination of the signal. An optional delay element is provided between a programmable interconnect structure and a destination logic element having a clock skew relative to the source. The optional delay element is programmed by the implementation software to introduce a delay on the signal path when necessary to meet the hold time requirements for the destination logic element. The optional delay is designed to be large enough to overcome hold-time violations even for the largest possible clock skew and the smallest possible signal delay. When no hold time violation occurs, the optional delay element is configured to bypass the additional delay, to avoid imposing a large setup requirement on the signal.

Abstract: An interconnect structure in which “diagonal” and “straight” interconnect lines are interleaved to minimize coupling between adjacent interconnect lines. An interconnect structure for an integrated circuit comprises rows and columns of tiles. Interconnect lines extend at least in part along a first column of the tiles, the interconnect lines including straight and diagonal interconnect lines. A “straight” interconnect line interconnects at least two tiles in the first column, and a “diagonal” interconnect line interconnects a tile in the first column with at least one tile in a different column and row. The interconnect lines are laid out in parallel fashion such that no straight interconnect line is physically adjacent to more than one other straight interconnect line, and no diagonal interconnect line is physically adjacent to more than one other diagonal interconnect line. Optionally, no two physically adjacent interconnect lines drive in the same direction within the first column.

Abstract: A 6-input LUT architecture includes 64 memory cells, which store 64 corresponding data values. Sixty-four write control circuits are coupled to the 64 memory cells. A first write address decoder receives a first subset of the six input signals, and in response, provides a first set of write select signals to the 64 write control circuits. A second write address decoder receives a second subset of the six input signals and a write clock signal, and in response, provides a plurality of decoded write clock signals to the sixty-four write control circuits. A write data value, which is applied to each of the write control circuits, is written to one of the memory cells in a synchronous manner with respect to the write clock signal in response to the first set of write select signals and the decoded write clock signals.

Abstract: A 6-input LUT architecture includes 64 memory cells, which store 64 corresponding data values. A set of 64 transmission gates is configured to receive the 64 four data values. A first input signal is applied to the set of 64 transmission gates, thereby routing 32 of the 64 data values. A set of 32 transmission gates is coupled to receive the 32 data values routed by the set of 64 transmission gates. A second input signal is applied to the set of 32 transmission gates, thereby routing 16 of the 32 data values. A 16:1 multiplexer receives the sixteen data values routed by the set of 32 transmission gates. Third, fourth, fifth and sixth input signals are applied to the 16:1 multiplexer, thereby routing one of the 16 data values as the output of the LUT.

Abstract: Structures enabling the efficient testing of interconnect in programmable logic devices (PLDS), and methods utilizing these structures. A PLD includes a non-homogeneous array of programmable logic blocks and an array of standardized interconnect blocks, where the same interconnect block is used for different types of logic blocks. Coupled between each of the interconnect blocks and the associated logic block is a standardized test structure, allowing the same test configuration to be used for each interconnect block even though the interconnect blocks are associated with logic blocks of different types. In some embodiments, one or more types of logic blocks are not associated with standardized test structures. These logic blocks are coupled directly to their associated interconnect blocks, and are preferably of a type that can be configured to emulate the standardized test structure. Thus, by a correct application of configuration data all of the interconnect blocks display the same behavior.