摘要:
An improved programmable logic device that generates output signals skewed in time includes a set of I/O cells and first and second logic circuits. Each logic circuit generates a logic output signal on a respective output line coupled to at least one of the I/O cells. A first delay element coupled to the output line of the first logic circuit is programmably operable to delay the output signal of the first logic circuit relative to the output signal of the second logic circuit in response to a first delay control signal. A second delay element coupled to the output line of the second logic circuit is programmably operable to delay the output signal of the second logic circuit relative to the output signal of the first logic circuit in response to a second delay control signal. Control circuitry generates the first and second delay control signals so as to prevent simultaneous switching of the logic output signals of the first and second logic circuits. This invention may be used to delay output signals which are not time-critical, allowing fast switching of the limited number of time-critical macrocell output signals.
摘要:
A programmable integrated circuit device includes a plurality of output terminals, each output terminal for use in transmitting a respective output signal. Timing control circuitry is connected to the output terminals. The timing control circuitry is operable to delay the output signal on each output terminal and is further operable to control a slew rate of the output signal on each output terminal.
摘要:
An improved programmable logic device includes a set of I/O cells, a set of logic blocks, and a routing pool that provides connections among the logic blocks and the I/O cells. At least one of the logic blocks includes a programmable logic array that generates product term output signals on product term output lines. A first product term summing circuit has input terminals, at least one of which is coupled to a product term output line. The first product term summing circuit generates an output signal at an output terminal in response to at least one product term output signal. Likewise, a second product term summing circuit has input terminals, at least one of which is coupled to a product term output line. The second product term summing circuit generates an output signal at an output terminal in response to at least one product term output signal. The logic block further includes first and second output lines and a first programmable switching device that programmably couples the first output line to the output terminal of either the first or the second product term summing circuit. The logic block further includes a second programmable switching device that programmably couples the second output line to the output terminal of either the first or the second product term summing circuit. The programmable logic device has increased functional capacity. In addition, generating an interconnect solution to program the programmable logic device is made simpler by the present invention.
摘要:
A circuit for providing programmable voltage output levels in a logic device includes a pull-up device for driving an output pad with either a first voltage output level or a second voltage output level. A charge pump generates a pumped voltage. A first clamp regulator, coupled to the charge pump and the pull-up device, receives a first reference signal. The first clamp regulator, in response to the first reference signal, generates a first voltage from which the first voltage output level is derived. A second clamp regulator, coupled to the pull-up device, receives a second reference signal. In response to the second reference signal, the second clamp regulator generates a second voltage from which the second voltage output level is derived. A passgate multiplexer is coupled to the first and second clamp regulators. The passgate multiplexer receives at least one output voltage select signal. In response to the at least one output voltage select signal the passgate multiplexer selects either the first voltage output level or the second voltage output level.
摘要:
An improved programmable logic device includes a set of I/O cells, a set of logic blocks, and a routing pool that provides connections among the logic blocks and the I/O cells. At least one of the logic blocks includes a programmable logic array that generates product term output signals on product term output lines. A first product term summing circuit has input terminals, at least one of which is coupled to a product term output line. The first product term summing circuit generates an output signal at an output terminal in response to at least one product term output signal. Likewise, a second product term summing circuit has input terminals, at least one of which is coupled to a product term output line. The second product term summing circuit generates an output signal at an output terminal in response to at least one product term output signal. The logic block further includes first and second output lines and a first programmable switching device that programmably couples the first output line to the output terminal of either the first or the second product term summing circuit. The logic block further includes a second programmable switching device that programmably couples the second output line to the output terminal of either the first or the second product term summing circuit. The programmable logic device has increased functional capacity. In addition, generating an interconnect solution to program the programmable logic device is made simpler by the present invention.
摘要:
A method for minimizing instantaneous currents ina signal bus is disclosed. The method involves providing a programmable delay element in each of the signal buffers driving the signal on the bus. The programmable delay element in each signal buffer is selectable enabled to include a predetermined time delay. The method involves programming the delay elements in a selected group of the signal buffers t includde the predetermined time delay, so that the selected group of signal buffers each generate an output signal switching after the predetermined delay relative to the switching of output signals generated by other signal buffers.
摘要:
An input/output circuit in an In-system programmable (ISP) logic device allows an output signal from a boundary scan register to be provided as output during programming operations of said ISP logic device. Thus, the ISP logic circuit can provide valid data output to other circuits interfaced to the ISP logic circuit during programming of the ISP logic device, thereby obviating a need to reset the system after reprogramming of the ISP logic device.
摘要:
An improved programmable logic device is disclosed. In one embodiment, the programmable logic device includes a plurality of I/O cells and a plurality of logic block clusters. Each logic block cluster has a set of logic blocks and a cluster routing pool, which provides programmable connections among the logic blocks and the I/O cells. A global routing pool provides programmable connections among the logic block clusters and the I/O cells. Each logic block includes a programmable logic array with a plurality of outputs. A product term sharing array in the logic block has a plurality of bus lines, each of which is coupled to at least one of the outputs of the programmable logic array. The product term sharing array also includes a plurality of output lines, each of which is coupled to a plurality of programmable interconnections that each provide a connection to one of the bus lines. Each output line of the product term sharing array is coupled to the same number of programmable interconnections. The logic block also includes a register coupled to at least one of the output lines of the product term sharing array. The register has a data input terminal and a data output terminal. First and second output multiplexers each have a first input terminal coupled to the data input terminal of the register and a second input terminal coupled to the data output terminal of the register.
摘要:
A programmable logic device includes a global clock structure and a plurality of localized clock structures. Each localized clock structure distributes a respective localized clock signal to a corresponding portion of the programmable logic device. The global clock structure distributes a global clock signal to all portion of the programmable logic device.
摘要:
An input/output circuit in an In-system programmable (ISP) logic device allows an output signal from a boundary scan register to be provided as output during programming operations of said ISP logic device. Thus, the ISP logic circuit can provide valid data output to other circuits interfaced to the ISP logic circuit during programming of the ISP logic device, thereby obviating a need to reset the system after reprogramming of the ISP logic device.