摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
In one embodiment, a clock distribution chip includes a first clock input adapted to receive a first single-ended input clock signal, a second clock input adapted to receive a second single-ended input clock signal, and input buffer circuitry coupled to the first and second clock inputs. The input buffer circuitry is adapted to select an input clock signal among the first single-ended input clock signal, the second single-ended input clock signal, and a differential input clock signal derived from the first and second single-ended input clock signals. A phase-locked loop (PLL) is adapted to receive an input clock signal selected by the input buffer circuitry and to generate a PLL clock signal based on the selected input clock signal. A clock output provides an output clock signal based on the PLL clock signal.
摘要:
A programmable logic block within a programmable logic device includes at least two interconnected slices, each of the interconnect slices including at least two interconnected lookup tables. Each interconnected lookup table is adapted to receive input signals from a routing structure and to provide a LUT output signal. At least one of the slices includes a register adapted to register the LUT output signal of a lookup table and at least another of the slices includes fewer such registers than lookup tables.
摘要:
Systems and methods are disclosed to provide clock generation. In accordance with one embodiment, a clock generator chip is provided that is configurable and in-system programmable. The clock generator chip may provide programmable input circuits, programmable output circuits, and permit a JTAG boundary scan.
摘要:
In one embodiment, a clock distribution chip includes a clock input adapted to receive an input clock signal, clock dividers each adapted to receive a clock signal based on the first input clock signal and to generate a divided clock signal, and programmable clock outputs adapted to provide output clock signals. The clock outputs are configurable to support a number of signaling standards. A programmable switch fabric is coupled between the clock dividers and the clock outputs and is configurable to provide the divided clock signals to the clock outputs.
摘要:
Programmable logic devices and techniques for programming and/or reconfiguring these devices are disclosed. For example, in accordance with an embodiment of the present invention, a programmable logic device is disclosed that incorporates flash memory and SRAM and includes multiple data ports for programming the flash memory and/or the SRAM.
摘要:
Systems and methods are disclosed to provide clock generation. In accordance with one embodiment, a clock generator chip is provided that is configurable and in-system programmable and includes a flexible skew control architecture. The clock generator chip may also provide programmable input circuits, programmable output circuits, and permit a JTAG boundary scan.