Abstract: An input buffer circuit provides programmable resistors for inputs to a microprocessor and compensates for switching voltage timing differences caused when a selected programmable resistor is utilized for a selected input. In a preferred embodiment, an input buffer circuit has a weak transistor coupled between the input and an operating voltage source or ground, and a compensation circuit including two transistors in series between the operating voltage source or ground, and an output. When the weak transistor is on, thereby raising or lowering the input signal, one of the transistors is also on and the other transistor couples the output to the operating voltage source or ground.

Abstract: The output driver includes a plurality of transistor devices connected to an output line. In one arrangement, a separate flash-programmable element is connected to each of the plurality of transistor devices. Each of the separate flash elements receives the data signal along an input line and outputs the data signal if the flash cell is enabled (or not programmed) and outputs a constant voltage level, regardless of the data signal, if the flash element is not enabled. Hence, only those output transistors connected to flash elements that have been enabled are triggered by the output signal. Other transistors merely receive a constant voltage and are, therefore, not triggered regardless of the output signal. In another arrangement, the output driver is configured to forward output signals to all of the output transistors but the flash cells are programmed to adjust a time delay occurring prior to reception by the output transistors.

Abstract: An integrated circuit incorporating programmable pullup and pulldown devices into each input/output (I/O) pad is described. Each I/O pad may be individually programmed to include a pullup or pulldown function. Pullup and pulldown resistors may be removed from a system employing the present integrated circuit. Programming of the I/O pads may be accomplished in a number of ways. Following the deassertion of a reset signal, high impedance states may be transferred into a shift data storage within the integrated circuit. Once the states are received, they are shifted to the respective I/O pads through a serial chain connection of the pullup and pulldown devices within each I/O pad. The states are then maintained by each pullup and pulldown device until a subsequent reprogramming. Software programs may also reprogram the pullup and pulldown states by storing appropriate values into the shift data storage. The program then sets an appropriate value into a status register included within the integrated circuit.

Abstract: A programmable drive strength buffer includes a control signal used to enable/disable an output drive transistor slew rate control circuit, and a current drive strength control bits which are used to select weak, medium or strong current drive capability over an ISA bus with loads varying from 60 pF to 240 pF for a supply voltage of 5.0 or 3.3 volts.

Abstract: A programmable logic cell has four logic gates, two of which are configurable. The two configurable logic gates are positioned near the logic cell inputs. Each configurable logic gate has two inputs, each input being connected to one of the four logic cell inputs. The remaining two logic gates receive the outputs of the configurable logic gates. Four independent logic cell input nodes are provided, each having associated therewith a programmable input multiplexer. Each input multiplexer can have inputs connected to at least two types of interconnect conductors. The cell also has two output paths, each having associated therewith an independently-controlled output multiplexer. The output of each output multiplexer is connected to an input of the other output multiplexer. Additional features include a multiplexer having inputs connected to two cell input nodes, a select input connected to a third logic cell input node, and an output connected to a cell output node; a system low-skew data (e.g.

Abstract: A user configurable circuit contains clock logic, a switching element and a data path circuit. Input data is received in the switching element, and the switching element and the data path circuit constitute the entire data path for the circuit. A plurality of user configurable inputs are received to configure the circuit for a particular user application. The clock logic and the switching element implement a logic function that is configurable by the user configurable inputs. The logic function is pre-processed in the clock logic so that minimal delay occurs in the data path. In addition, the propagation delay through the switching element and the register is independent of the user configurable inputs. The user configurable circuit of the present invention has application for use as a macro cell for a programmable logic device permitting the user to configure the circuit as a D-type flip-flop, a T-type flip-flop. In addition, the user selects the polarity for the output circuit.

Abstract: Architecture for a programmable logic device is described which can operate at substantially faster clock rates than present programmable logic devices. The PLD uses BiCMOS circuit elements to make use of the speed advantages of bipolar technology while also enjoying the limited power consumption of CMOS technology.

Abstract: An input/output buffer including a bidirectional node, an output stage, an input stage, and a control circuit. The output stage has a first n-channel transistor coupled between the bidirectional node and a voltage supply node for pulling-up the bidirectional node, and first and second p-channel transistors coupled between the bidirectional node and the voltage supply node for pulling-up the bidirectional node. The input stage has a first inverter stage coupled between the bidirectional node and a first intermediate node and a second inverter stage coupled between the bidirectional node and a second intermediate node. The input stage also has a second n-channel transistor coupled between the first intermediate node and a ground node and a third n-channel transistor coupled between the second intermediate node and the ground node. The control circuit is coupled to the output stage and to the input stage and enables the output stage when in an output mode and disables the output stage when in an input mode.

Abstract: A CMOS circuit is disclosed for translating a signal from CML to CMOS logic voltage levels. The CMOS circuit includes two amplifier circuits coupled in parallel. The first amplifier circuit comprises of a programmable circuit and a CMOS inverter such that the CMOS inverter can be programmed "on" or "off" by the programmable circuit. The programmable circuit includes a programmable element which may be implemented using a fuse or floating gate technology. The second amplifying circuit comprises of a CMOS inverter. When the CMOS inverter in the first amplifier circuit is powered "on", the CMOS circuit is operating in a full power mode at high speed with both CMOS inverters operating. When the CMOS inverter in the first amplifier circuit is powered "off", the CMOS circuit is operating in a low power mode at a slower speed with only one CMOS inverter operating.

Abstract: A configurable NAND/NOR logic element is used, in an exemplary embodiment, in an array of spare gates included in a processor or other integrated circuit. The NAND/NOR logic element (FIG. 3, 50) is configurable as either a NAND or a NOR gate by a C (configuration) input (that can be metal configurable as either asserted or deasserted). C inputs control p- and n-channel transistors. Depending on whether the C input is deasserted or asserted, respective internal nodes are shorted to effect the selected configuration. Specifically, deasserting C provides the NAND configuration, while asserting C provides the NOR configuration. In an alternative embodiment, the NAND/NOR logic element can be used in a full adder to provide the carry output.

Abstract: According to the present invention, an integrated circuit device is capable of responding to more than one input threshold voltage level by making only minimal changes to the device. The input buffer of the integrated circuit device is modified to be a programmable buffer that is controlled by a control input signal which may be generated by several different control means. Such control means include a bond option, a mask option, a fuse option, a register option, and a voltage detector option.

Abstract: A polarity control circuit for selectively providing a signal received at a data port to a first output port, and a second complementary output port, with a state as determined by a polarity selection signal provided to the polarity control circuit. The polarity control circuit includes circuitry configured to reduce gate delays.

Abstract: An integrated circuit is presented having a driver circuit programmable to produce a variety of output voltages and conductive to the voltage levels of circuits interfaced by the integrated circuit. The integrated circuit includes programmable pullup and pulldown functions. The integrated circuit may be configured into an application having devices powered by a power supply voltage which is substantially larger than the voltage supplying the core section of the integrated circuit. Additionally, the present integrated circuit may be configured into other applications having devices powered by a power supply voltage substantially similar to the voltage supplying the integrated circuit core section. The present integrated circuit therefore retains utility for a large variety of applications. The pullup and pulldown transistors may be programmed to provide a resistive one, resistive zero, or neither.

Abstract: A circuit for selecting a block spare in a semiconductor device is designed with a programmable circuit (14), storing an internal address and producing an address match signal AM and a block select signal BS in response to first (A) and second (B) address signals and the internal address. A global spare circuit (28) produces a global spare select signal (GSS), in response to the address match signal. A block spare circuit (34) produces a block spare select signal (BSS), in response to the global spare select signal and the block select signal.

Abstract: A user configurable circuit contains clock logic, a switching element and a data path circuit. Input data is received in the switching element, and the switching element and the data path circuit constitute the entire data path for the circuit. A plurality of user configurable inputs are received to configure the circuit for a particular user application. The clock logic and the switching element implement a logic function that is configurable by the user configurable inputs. The logic function is pre-processed in the clock logic so that minimal delay occurs in the data path. In addition, the propagation delay through the switching element and the register is independent of the user configurable inputs. The user configurable circuit of the present invention has application for use as a macro cell for a programmable logic device permitting the user to configure the circuit as a D-type flip-flop, a T-type flip-flop. In addition, the user selects the polarity for the output circuit.

Abstract: A base cell for a CMOS gate array is provided with a plurality of N-channel transistors 10, 12, 14 with all such N-channel transistors coupled in series. A plurality of P-channel transistors 16, 18 coupled in series. These transistors are interconnected at the transistor level to form a partially prewired circuit. Specifically, the gates of two of the N-channel transistors 12, 14 are connected by polysilicon lead 28 to the gate of transistor 16. This configuration forms a circuit primitive which is well adapted for use as a base cell in a programmable array device.

Abstract: A method and circuit for selectively or programmably controlling the polarity of a signal includes a two transistor invertor with its sources coupled to a select signal and its complement and its drains coupled to buffer circuits that pull the drains to full CMOS voltage rail levels. The circuit consumes no standby current and is fully restoring.

Abstract: A method and circuit are disclosed which can be incorporated into any circuitry which uses fused algorithms to control the circuitry. Specifically, the invention may be incorporated into an integrated circuit device by way of a circuit that controls the coupling of an input signal to an output. Careful placement of a fuse or similarly functioning element in the circuit, permits the output of said circuit to be reliably set to a desired logic state. Specifically, when the fuse element is opened, a portion of the feedback path is disconnected, thereby preventing feedback in the direction of the unwanted logic state. The present invention enables construction of a fuse circuit which latches a desired logic state with stable performance and no layout area or speed degradation.

Abstract: A source follower circuit which operates at high speed and maintains low power consumption and which includes a pair of small, normally on, NMOS and PMOS transistors and a pair of large, normally off, NMOS and PMOS transistors. The two pairs of transistors are connected in parallel. In each pair of transistors the sources and the gates of the NMOS and PMOS transistors are connected to each other. Furthermore, the threshold voltages of the transistors must be set so that: large NMOS transistor voltage>small PMOS transistor voltage>small NMOS transistor voltage>large PMOS transistor voltage, or so that small PMOS transistor voltage>large NMOS transistor voltage>large PMOS transistor voltage>small NMOS transistor voltage.

Abstract: A programmable logic output driver includes a bias generator (100), a current mirror (200) and an output stage (300), there being a digital programming feature to maintain the output voltage slew rate at an acceptable value for either high or low values of load capacitances. The driver is programmable and can maintain a constant value of driver output resistance in the circumstances where the load voltage approaches the full swing logic voltage. In the preferred embodiment, the programmed output resistance is independent of variations in process, temperature and VDD supply voltage. TTL loads are driven with the minimum amount of required output current. Because of the constant resistance, the driver supplies a specified amount of current to the load even when the load is pulled down to a specified voltage.

Abstract: A CMOS LSI stably operates with high speed ECL LSI's to provide a data processing system. Two power sources of a negative ECL operation voltage and a positive CMOS operation voltage are provided. In a CMOS LSI, input signals of ECL level are successively amplified through an ECL input interface having a p-channel differential amplifier and an n-channel type differential amplifier, fed to the CMOS output buffer circuit and converted to the CMOS level, processed in a CMOS internal circuit, and output at the ECL level through output open-drain MOSFETs. The CMOS LSI is operated by two power sources which are level-shifted in correspondence with the ECL signal amplitude, instead of using ground potential and a positive voltage such as VDD.

Abstract: A base cell for a CMOS gate array is provided with a first plurality of N-channel transistors 12, 14, 16 with two such N-channel transistors coupled in series. A first plurality of P-channel transistors 50, 52, 54 with two such P-channel transistors coupled in series. These transistors are interconnected at the transistor level to form a partially prewired circuit. Additional pairs of series connected N-channel transistors (18, 20), (22, 24) and pairs of series connected P-channel transistors (56, 58), (60, 62) are also provided and are interconnected at the transistor level to form additional partially prewired circuits. By adding additional levels of wiring 100, 102, the base cell can be finally wired to form a plurality of different logic circuits.

Abstract: A base cell for a CMOS gate array is provided with a plurality of N-channel transistors 10 and a plurality of P-channel transistors 12. These transistors are interconnected at the transistor level to form a partially prewired circuit. Additional N-channel (14) and P-channel (70, 72) transistors are included in the base cell at least some of which are larger in size than those in the plurality of N-channel transistors 10 or the plurality of P-channel transistors 12. These larger size transistors are used as output drivers to send the logical output signal of the cell to another cell.