ABEL Advanced Boolean Expression Language (ABEL) is a high-level language (HDL) and compilation system produced by Data I/O Corporation. ABEL-HDL File The ABEL-HDL (ABL) file is a file written in ABEL Hardware Description Language that contains logic expressed as equations, truth tables, and state machine descriptions. accumulator An accumulator is a register for adding, subtracting, or both. adder An adder is a combinatorial circuit that computes the sum of two or more numbers. architecture Architecture is the common logic structure of a family of programmable integrated circuits. The same architecture can be realized in different manufacturing processes. Examples of Xilinx architectures are the Virtex2 , Virtex2Pro, CoolRunner2, and XC9500 devices. analyze The first step in the synthesis flow. In this stage, the HDL code is checked for syntax errors. annotation Annotation is the insertion of simulation values into the schematic. area constraints Area constraints are created by the user or a process such as synthesis to direct the optimization process that takes place during design implementation. arithmetic equations Arithmetic equations specify the special arithmetic capabilities of the Xilinx CPLDs. Arithmetic Logic Unit (ALU) A logic function that performs arithmetic computations, such as addition, multiplication, and comparison operations. The ALU is one component of the Central Processing Unit (CPU). ASIC Application-specific integrated circuit (ASIC), is a full-custom circuit. In which every mask is defined by the customer or a semi-custom circuit (gate array) where only a few masks are defined. asynchronous debugging Asynchronous debugging is a debugging mode in which you capture data without controlling your system clock. asynchronous logic Asynchronous logic changes independently of clock changes. A signal whose intended function is performed immediately at the point the signal is asserted without regard to a clock. Asynchronous Transfer Mode (ATM) ATM is a method of transmitting voice, data, and video in fixed-size packets over high-speed telecommunications channels. attributes Attributes are instructions placed on symbols or nets in an FPGA or CPLD schematic to indicate their placement, implementation, naming, directionality, or other properties. |
back-annotation Back-annotation is the translation of a routed or fitted design to a timing simulation netlist. behavioral design Behavioral design is a technology-independent, text-based design that incorporates high-level functionality and high-level information flow. behavioral design method A behavioral design method defines a circuit in terms of a textual language rather than a schematic of interconnected symbols. behavioral simulation Also known as functional simulation. Behavioral simulation is usually performed on designs that are entered using a hardware definition language (HDL). This type of simulation takes place during the pre-synthesis stage of HDL design. Functional simulation checks that the HDL code describes the desired design behavior. Behavioral simulation is a simulation process that is performed by interpreting the equations that define the design. The equations do not need to be converted to the logic that represents them. binary encoding Binary or maximal encoding is a type of state machine encoding that uses the minimum number of registers to encode the machine. Each register is used to its maximum capability. bit A bit is a binary digit representing 0 or 1. BIT file A BIT file is the same as a bitstream file. See bitstream. BitGen Is a program that produces a bitstream for Xilinx device configuration. BitGen takes a fully routed NCD (Circuit Description) file as its input and produces a configuration bitstream, a binary file with a .bit extension. bitstream A bitstream is a stream of data that contains location information for logic on a device, that is, the placement of Configurable Logic Blocks (CLBs), Input/Output Blocks (IOBs), (TBUFs), pins, and routing elements. The bitstream also includes empty placeholders that are filled with the logical states sent by the device during a readback. Only the memory elements, such as flip-flops, RAMs, and CLB outputs, are mapped to these placeholders, because their contents are likely to change from one state to another. When downloaded to a device, a bitstream configures the logic of a device and programs the device so that the states of that device can be read back. A bitstream file has a .bit extension. block 1. A block is a group of one or more logic functions. 2. A block is a schematic or symbol sheet. There are four types of blocks. A Composite block indicates that the design is hierarchical. A Module block is a symbol with no underlying schematic. A Pin block represents a schematic pin. An Annotate block is a symbol without electrical connectivity that is used only for documentation and graphics. boundary scan Boundary scan is the method used for board-level testing of electronic assemblies. The primary objectives are the testing of chip I/O signals and the interconnections between ICs. It is the method for observing and controlling all new chip I/O signals through a standard interface called a Test Access Port (TAP). The boundary scan architecture includes four dedicated I/O pins for control and is described in IEEE spec 1149.1. buffer A buffer is an element used to increase the current or drive of a weak signal and, consequently, increase the fanout of the signal. A storage element. BUFT A BUFT is a tristate buffer. bus A group of two or more signals that carry closely-associated signals in an electronic design. |
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