Functional Categories

Libraries GuideChapter 2: Selection Guide

Functional Categories

This section categorizes, by function, the logic elements that are described in detail in the “Design Elements” sections. Each category is briefly described. Tables under each category identify all the available elements for the function and indicate which libraries include the element.

Elements are listed in alphanumeric order under each category. There are a number of standard TTL 7400-type functions in the different libraries. All 7400-type functions start with a “X74” prefix and are listed after all other elements. The numeric sequence following the “X74” prefix uses ascending numbers, for example, X74_42 precedes X74_138.

A check mark () in the column under the library name means that the element applies to the devices that use that library. (Refer to the “Applicable Architectures” section of the “Xilinx Unified Libraries” chapter for information on the specific device families that use each library.) A blank column means that the element does not apply.

The categories are as follows.

Note: When converting your design between FPGA families, use elements that have equivalent functions in each of the architectural families (libraries) to minimize re-designing.

Arithmetic Functions

There are three types of arithmetic functions: accumulators (ACC), adders (ADD), and adder/subtracters (ADSU). With an ADSU, either unsigned binary or twos-complement operations cause an overflow. If the result crosses the overflow boundary, an overflow is generated. Similarly, when the result crosses the carry-out boundary, a carry-out is generated. The following figure shows the ADSU carry-out and overflow boundaries.

Figure 2.1 ADSU Carry-Out and Overflow Boundaries

ACC1		1-Bit Loadable Cascadable Accumulator with Carry-In, Carry-Out, and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ACC4, 8, 16		4-, 8-, 16-Bit Loadable Cascadable Accumulators with Carry-In, Carry-Out, and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ADD1		1-Bit Full Adder with Carry-In and Carry-Out
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ADD4, 8, 16		4-, 8-, 16-Bit Cascadable Full Adders with Carry-In, Carry-Out, and Overflow
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ADSU1		1-Bit Cascadable Adder/Subtracter with Carry-In, Carry-Out
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ADSU4, 8, 16		4-, 8-, 16-Bit Cascadable Adders/Subtracters with Carry-In, Carry-Out and Overflow
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_280		9-Bit Odd/Even Parity Generator/Checker
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_283		4-Bit Full Adder with Carry-In and Carry-Out
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Buffers

The buffers in this section route high fan-out signals, 3-state signals, and clocks inside a PLD device. The “Input/Output Functions” section later in this chapter covers off-chip interface buffers.

ACLK		Alternate Clock Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUF		General-Purpose Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUF4, 8, 16		General-Purpose Buffers
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFCF		Fast Connect Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFE, 4, 8, 16		Internal 3-State Buffers with Active High Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex
				*
* not supported for XC9500XL and XC9500XV devices

BUFFCLK		Global Fast Clock Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFG		Global Clock Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGDLL		Clock Delay Locked Loop Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGE		Global Low Early Clock Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGLS		Global Low Skew Clock Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGP		Primary Global Buffer for Driving Clocks or Longlines (Four per PLD Device)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGS		Secondary Global Buffer for Driving Clocks or Longlines (Four per PLD Device)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGSR		Global Set/Reset Input Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFGTS		Global Three-State Input Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFOD		Open-Drain Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BUFT, 4, 8, 16		Internal 3-State Buffers with Active-Low Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex
				*
* not supported for XC9500XL and XC9500XV devices

GCLK		Global Clock Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Comparators

There are two types of comparators, identity (COMP) and magnitude (COMPM).

COMP2, 4, 8, 16		2-, 4-, 8-, 16-Bit Identity Comparators
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

COMPM2, 4, 8, 16		2-, 4-, 8-, 16-Bit Magnitude Comparators
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

COMPMC8, 16		8-, 16-Bit Magnitude Comparators
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_L85		4-Bit Expandable Magnitude Comparator
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_518		8-Bit Identity Comparator with Active-Low Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_521		8-Bit Identity Comparator with Active-Low Enable and Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Counters

There are six types of counters with various synchronous and asynchronous inputs. The name of the counter defines the modulo or bit size, the counter type, and which control functions are included. The counter naming convention is shown in the following figure.

Figure 2.2 Counter Naming Convention

A carry-lookahead design accommodates large counters without extra gating. On TTL 7400-type counters with trickle clock enable (ENT), parallel clock enable (ENP), and ripple carry-out (RCO), both the ENT and ENP inputs must be High to count. ENT is propagated forward to enable RCO, which produces a High output with the approximate duration of the QA output. The following figure illustrates a carry-lookahead design.

Figure 2.3 Carry-Lookahead Design

The RCO output of the first stage of the ripple carry is connected to the ENP input of the second stage and all subsequent stages. The RCO output of the second stage and all subsequent stages is connected to the ENT input of the next stage. The ENT of the second stage is always enabled/tied to VCC. CE is always connected to the ENT input of the first stage. This cascading method allows the first stage of the ripple carry to be built as a prescaler. In other words, the first stage is built to count very fast.

CB2CE, CB4CE, CB8CE, CB16CE		2-, 4-, 8-, 16-Bit Cascadable Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CB2CLE, CB4CLE, CB8CLE, CB16CLE		2-, 4-, 8-, 16-Bit Loadable Cascadable Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CB2CLED, CB4CLED, CB8CLED, CB16CLED		2-, 4-, 8-, 16-Bit Loadable Cascadable Bidirectional Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CB2RE, CB4RE, CB8RE, CB16RE		2-, 4-, 8-, 16-Bit Cascadable Binary Counters with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CB2RLE, CB4RLE, CB8RLE, CB16RLE		2-, 4-, 8-, 16-Bit Loadable Cascadable Binary Counters with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CB2X1, CB4X1, CB8X1, CB16X1		2-, 4-, 8-, 16-Bit Loadable Cascadable Bidirectional Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CB2X2, CB4X2, CB8X2, CB16X2		2-, 4-, 8-, 16-Bit Loadable Cascadable Bidirectional Binary Counters with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CC8CE, CC16CE		8-, 16-Bit Cascadable Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CC8CLE, CC16CLE		8-, 16-Bit Loadable Cascadable Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CC8CLED, CC16CLED		8-, 16-Bit Loadable Cascadable Bidirectional Binary Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CC8RE, CC16RE		8-, 16-Bit Cascadable Binary Counters with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CD4CE		4-Bit Cascadable BCD Counter with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CD4CLE		4-Bit Loadable Cascadable BCD Counter with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CD4RE		4-Bit Cascadable BCD Counter with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CD4RLE		4-Bit Loadable Cascadable BCD Counter with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CJ4CE, CJ5CE, CJ8CE		4-, 5-, 8-Bit Johnson Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CJ4RE, CJ5RE, CJ8RE		4-, 5-, 8-Bit Johnson Counters with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CR8CE, CR16CE		8-, 16-Bit Negative-Edge Binary Ripple Counters with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_160		4-Bit BCD Counter with Parallel and Trickle Enables, Active-Low Load Enable, and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_161		4-Bit Binary Counter with Parallel and Trickle Enables, Active-Low Load Enable, and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_162		4-Bit BCD Counter with Parallel and Trickle Enables, Active-Low Load Enable, and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_163		4-Bit Binary Counter with Parallel and Trickle Enables, Active-Low Load Enable, and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_168		4-Bit BCD Bidirectional Counter with Parallel and Trickle Clock Enables and Active-Low Load Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_390		4-Bit BCD/Bi-Quinary Ripple Counter with Negative-Edge Clocks and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Data Registers

There are three TTL 7400-type data registers designed to function exactly as the TTL elements for which they are named.

X74_174		6-Bit Data Register with Active-Low Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_273		8-Bit Data Register with Active-Low Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_377		8-Bit Data Register with Active-Low Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Decoders

Decoder names, shown in the following figure, indicate the number of inputs and outputs and if an enable is available. Decoders with an enable can be used as multiplexers. This group includes some standard TTL 7400-type decoders whose names have an “X74” prefix.

Figure 2.4 Decoder Naming Convention

D2_4E		2- to 4-Line Decoder/Demultiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

D3_8E		3- to 8-Line Decoder/Demultiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

D4_16E		4- to 16-Line Decoder/Demultiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

DEC_CC4, 8, 16		4-, 8-, 16-Bit Active Low Decoders
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_42		4- to 10-Line BCD-to-Decimal Decoder with Active-Low Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_138		3- to 8-Line Decoder/Demultiplexer with Active-Low Outputs and Three Enables
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_139		2- to 4-Line Decoder/Demultiplexer with Active-Low Outputs and Active-Low Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_154		4- to 16-Line Decoder/Demultiplexer with Two Enables and Active-Low Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Edge Decoders

Edge decoders are open-drain wired-AND gates that are available in different bit sizes.

DECODE4, 8, 16		4-, 8-, 16-Bit Active-Low Decoders
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

DECODE32, 64		32- and 64-Bit Active-Low Decoders
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Encoders

There are two priority encoders (ENCPR) that function like the TTL 7400-type elements they are named after. There is a 10- to 4-line BCD encoder and an 8- to 3-line binary encoder.

X74_147		10- to 4-Line Priority Encoder with Active-Low Inputs and Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_148		8- to 3-Line Cascadable Priority Encoder with Active-Low Inputs and Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Flip-Flops

There are three types of flip-flops (D, J-K, toggle) with various synchronous and asynchronous inputs. Some are available with inverted clock inputs and/or the ability to set in response to global set/reset rather than reset. The naming convention shown in the following figure provides a description for each flip-flop. D-type flip-flops are available in multiples of up to 16 in one macro.

Figure 2.5 Flip-Flop Naming Convention

FD		D Flip-Flop
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FD_1		D Flip-Flop with Negative-Edge Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FD4, 8, 16		Multiple D Flip-Flops
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FD4CE, FD8CE, FD16CE		4-, 8-, 16-Bit Data Registers with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FD4RE, FD8RE, FD16RE		4-, 8-, 16-Bit Data Registers with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDC		D Flip-Flop with Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDC_1		D Flip-Flop with Negative-Edge Clock and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDCE		D Flip-Flop with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDCE_1		D Flip-Flop with Negative-Edge Clock, Clock Enable, and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDCP		D Flip-Flop with Asynchronous Preset and Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDCP_1		D Flip-Flop with Negative-Edge Clock and Asynchronous Preset and Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDCPE		D Flip-Flop with Clock Enable and Asynchronous Preset and Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDCPE_1		D Flip-Flop with Negative-Edge Clock, Clock Enable, and Asynchronous Preset and Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDE		D Flip-Flop with Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDE_1		D Flip-Flop with Negative-Edge Clock and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDP		D Flip-Flop with Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDP_1		D Flip-Flop with Negative-Edge Clock and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDPE		D Flip-Flop with Clock Enable and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDPE_1		D Flip-Flop with Negative-Edge Clock, Clock Enable, and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDR		D Flip-Flop with Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDR_1		D Flip-Flop with Negative-Edge Clock and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDRE		D Flip-Flop with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDRE_1		D Flip-Flop with Negative-Clock Edge, Clock Enable, and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDRS		D Flip-Flop with Synchronous Reset and Synchronous Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDRS_1		D Flip-Flop with Negative-Clock Edge and Synchronous Reset and Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDRSE		D Flip-Flop with Synchronous Reset and Set and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDRSE_1		D Flip-Flop with Negative-Clock Edge, Synchronous Reset and Set, and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDS		D Flip-Flop with Synchronous Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDS_1		D Flip-Flop with Negative-Edge Clock and Synchronous Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDSE		D Flip-Flop with Clock Enable and Synchronous Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDSE_1		D Flip-Flop with Negative-Edge Clock, Clock Enable, and Synchronous Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDSR		D Flip-Flop with Synchronous Set and Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FDSRE		D Flip-Flop with Synchronous Set and Reset and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKC		J-K Flip-Flop with Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKCE		J-K Flip-Flop with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKCP		J-K Flip-Flop with Asynchronous Clear and Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKCPE		J-K Flip-Flop with Asynchronous Clear and Preset and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKP		J-K Flip-Flop with Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKPE		J-K Flip-Flop with Clock Enable and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKRSE		J-K Flip-Flop with Clock Enable and Synchronous Reset and Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FJKSRE		J-K Flip-Flop with Clock Enable and Synchronous Set and Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTC		Toggle Flip-Flop with Toggle Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTCE		Toggle Flip-Flop with Toggle and Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTCLE		Toggle/Loadable Flip-Flop with Toggle and Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTCLEX		Toggle/Loadable Flip-Flop with Toggle and Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTCP		Toggle Flip-Flop with Toggle Enable and Asynchronous Clear and Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTCPE		Toggle Flip-Flop with Toggle and Clock Enable and Asynchronous Clear and Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTCPLE		Loadable Toggle Flip-Flop with Toggle and Clock Enable and Asynchronous Clear and Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTP		Toggle Flip-Flop with Toggle Enable and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTPE		Toggle Flip-Flop with Toggle and Clock Enable and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTPLE		Toggle/Loadable Flip-Flop with Toggle and Clock Enable and Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTRSE		Toggle Flip-Flop with Toggle and Clock Enable and Synchronous Reset and Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTRSLE		Toggle/Loadable Flip-Flop with Toggle and Clock Enable and Synchronous Reset and Set
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTSRE		Toggle Flip-Flop with Toggle and Clock Enable and Synchronous Set and Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FTSRLE		Toggle/Loadable Flip-Flop with Toggle and Clock Enable and Synchronous Set and Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

General

General elements include FPGA configuration functions, oscillators, boundary scan logic, and other functions not classified in other sections.

BSCAN		Boundary Scan Logic Control Circuit
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BSCAN_SPARTAN2		Spartan2 Boundary Scan Logic Control Circuit
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BSCAN_VIRTEX		Virtex Boundary Scan Logic Control Circuit
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

BYPOSC		Bypass Oscillator
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CAPTURE_SPARTAN2		Spartan2 Register State Capture for Bitstream Readback
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CAPTURE_VIRTEX		Virtex Register State Capture for Bitstream Readback
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CK_DIV		Internal Multiple-Frequency Clock Divider
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CLB		CLB Configuration Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CLKDLL		Clock Delay Locked Loop
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CLKDLLHF		High Frequency Clock Delay Locked Loop
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CONFIG		Repository for Schematic-Level (Global) Attributes
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

CY_INIT		Initialization Stage for Carry Chain
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

GND		Ground-Connection Signal Tag
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

GXTL		Crystal Oscillator with ACLK Buffer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IOB		IOB Configuration Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

KEEPER		KEEPER Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LUT1, 2, 3, 4		1-, 2-, 3-, 4-Bit Look-Up-Table with General Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LUT1_D, LUT2_D, LUT3_D, LUT4_D		1-, 2-, 3-, 4-Bit Look-Up-Table with Dual Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LUT1_L, LUT2_L, LUT3_L, LUT4_L		1-, 2-, 3-, 4-Bit Look-Up-Table with Local Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MD0		Mode 0, Input Pad Used for Readback Trigger Input
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MD1		Mode 1, Output Pad Used for Readback Data Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MD2		Mode 2, Input Pad
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OSC		Crystal Oscillator Amplifier
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OSC4		Internal 5-Frequency Clock-Signal Generator
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OSC5		Internal Multiple-Frequency Clock-Signal Generator
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OSC52		Internal Multiple-Frequency Clock-Signal Generator
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

PULLDOWN		Resistor to GND for Input Pads
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

PULLUP		Resistor to VCC for Input PADs, Open-Drain, and 3-State Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

READBACK		FPGA Bitstream Readback Controller
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

STARTUP		User Interface to Global Clock, Reset, and 3-State Controls
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

STARTUP_SPARTAN2		Spartan2 User Interface to Global Clock, Reset, and 3-State Controls
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

STARTUP_VIRTEX		Virtex User Interface to Global Clock, Reset, and 3-State Controls
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

TCK		Boundary Scan Test Clock Input Pad
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

TDI		Boundary Scan Test Data Input Pad
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

TDO		Boundary Scan Data Output Pad
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

TIMEGRP		Schematic-Level Table of Basic Timing Specification Groups
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

TIMESPEC		Schematic-Level Timing Requirement Table
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

TMS		Boundary Scan Test Mode Select Input Pad
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

VCC		VCC-Connection Signal Tag
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Input/Output Flip-Flops

Input/Output flip-flops are configured in IOBs. They include flip-flops whose outputs are enabled by 3-state buffers, flip-flops that can be set upon global set/reset rather than reset, and flip-flops with inverted clock inputs. The naming convention specifies each flip-flop function and is illustrated in the following figure.

Figure 2.6 Input/Output Flip-Flop Naming Convention

IFD, 4, 8, 16		Single- and Multiple-Input D Flip-Flops
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFD_1		Input D Flip-Flop with Inverted Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFDI		Input D Flip-Flop (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFDI_1		Input D Flip-Flop with Inverted Clock (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFDX, 4, 8, 16		Single- and Multiple-Input D Flip-Flops with Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFDX_1		Input D Flip-Flop with Inverted Clock and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFDXI		Input D Flip-Flop with Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IFDXI_1		Input D Flip-Flop with Inverted Clock and Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFD, 4, 8, 16		Single- and Multiple-Output D Flip-Flops
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFD_1		Output D Flip-Flop with Inverted Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDE, 4, 8, 16		D Flip-Flops with Active-High Enable Output Buffers
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDE_1		D Flip-Flop with Active-High Enable Output Buffer and Inverted Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDEI		D Flip-Flop with Active-High Enable Output Buffer (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDEI_1		D Flip-Flop with Active-High Enable Output Buffer and Inverted Clock (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDEX, 4, 8, 16		D Flip-Flops with Active-High Enable Output Buffers and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDEX_1		D Flip-Flop with Active-High Enable Output Buffer, Inverted Clock, and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDEXI		D Flip-Flop with Active-High Enable Output Buffer and Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDEXI_1		D Flip-Flop with Active-High Enable Output Buffer, Inverted Clock, and Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDI		Output D Flip-Flop (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDI_1		Output D Flip-Flop with Inverted Clock (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDT, 4, 8, 16		Single and Multiple D Flip-Flops with Active-Low 3-State Output Buffers
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDT_1		D Flip-Flop with Active-Low 3-State Output Buffer and Inverted Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDTI		D Flip-Flop with Active-Low 3-State Output Buffer (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDTI_1		D Flip-Flop with Active-Low 3-State Output Buffer and Inverted Clock (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDTX, 4, 8, 16		Single and Multiple D Flip-Flops with Active-Low 3-State Output Buffers and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDTX_1		D Flip-Flop with Active-Low 3-State Output Buffer, Inverted Clock, and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDTXI		D Flip-Flop with Active-Low 3-State Output Buffer and Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDTXI_1		D Flip-Flop with Active-Low 3-State Output Buffer, Inverted Clock, and Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDX, 4, 8, 16		Single- and Multiple-Output D Flip-Flops with Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDX_1		Output D Flip-Flop with Inverted Clock and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDXI		Output D Flip-Flop with Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OFDXI_1		Output D Flip-Flop with Inverted Clock and Clock Enable (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Input/Output Functions

Input/Output Block (IOB) resources are configured into various I/O primitives and macros for convenience, such as, output buffers (OBUFs) and output buffers with an enable (OBUFEs). Pads used to connect the circuit to PLD device pins are also included.

Virtex and Spartan2 have multiple variants (primitives) to choose from for each selectI/O buffer. The I/O interface for each variant corresponds to a specific I/O standard.

IBUF, 4, 8, 16		Single- and Multiple-Input Buffers
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IBUF_selectIO		Single Input Buffer with Selectable I/O Interface (16 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IBUFG_selectIO		Dedicated Input Buffer with Selectable I/O Interface (16 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IOBUF_selectIO		Bi-Directional Buffer with Selectable I/0 Interface (30 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IOPAD, 4, 8, 16		Single- and Multiple-Input/Output Pads
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

IPAD, 4, 8, 16		Single- and Multiple-Input Pads
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OBUF, 4, 8, 16		Single- and Multiple-Output Buffers
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OBUF_selectIO		Single Output Buffer with Selectable I/O Interface (30 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OBUFE, 4, 8, 16		3-State Output Buffers with Active-High Output Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OBUFT, 4, 8, 16		Single and Multiple 3-State Output Buffers with Active Low Output Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OBUFT_selectIO		Single 3-State Output Buffer with Active-Low Output Enable and Selectable I/O Interface (30 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OPAD, 4, 8, 16		Single- and Multiple-Output Pads
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

UPAD		Connects the I/O Node of an IOB to the Internal PLD Circuit
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Input Latches

Single and multiple input latches can hold transient data entering a chip. Input latches use the same naming convention as I/O flip-flops.

ILD, 4, 8, 16		Transparent Input Data Latches
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILD_1		Transparent Input Data Latch with Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILDI		Transparent Input Data Latch (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILDI_1		Transparent Input Data Latch with Inverted Gate (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILDX, 4, 8, 16		Transparent Input Data Latches
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILDX_1		Transparent Input Data Latch with Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILDXI		Transparent Input Data Latch (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILDXI_1		Transparent Input Data Latch with Inverted Gate (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILFFX		Fast Capture Input Latch
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILFFXI		Fast Capture Input Latch (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILFLX		Fast Capture Transparent Input Latch
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILFLX_1		Fast Capture Input Latch with Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ILFLXI_1		Fast Capture Input Latch with Inverted Gate (Asynchronous Preset)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Latches

Latches (LD) are only available in the XC4000X, XC5200, XC9000, Spartan2, SpartanXL, and Virtex architectures. XC3000 and XC4000E latches that existed in previous macro libraries are not recommended for new designs.

LD		Transparent Data Latch
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LD_1		Transparent Data Latch with Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LD4, 8, 16		Multiple Transparent Data Latches
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDC		Transparent Data Latch with Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDC_1		Transparent Data Latch with Asynchronous Clear and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDCE		Transparent Data Latch with Asynchronous Clear and Gate Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDCE_1		Transparent Data Latch with Asynchronous Clear, Gate Enable, and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LD4CE, LD8CE, LD16CE		Transparent Data Latches with Asynchronous Clear and Gate Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDCP		Transparent Data Latch with Asynchronous Clear and Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDCP_1		Transparent Data Latch with Asynchronous Clear and Preset and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDCPE		Transparent Data Latch with Asynchronous Clear and Preset and Gate Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDCPE_1		Transparent Data Latch with Asynchronous Clear and Preset, Gate Enable, and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDE		Transparent Data Latch with Gate Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDE_1		Transparent Data Latch with Gate Enable and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDP		Transparent Data Latch with Asynchronous Preset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDP_1		Transparent Data Latch with Asynchronous Preset and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDPE		Transparent Data Latch with Asynchronous Preset and Gate Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

LDPE_1		Transparent Data Latch with Asynchronous Preset, Gate Enable, and Inverted Gate
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Logic Primitives

Combinatorial logic gates that implement the basic Boolean functions are available in all architectures with up to five inputs in all combinations of inverted and non-inverted inputs, and with six to nine inputs non-inverted.

AND2-9		2- to 9-Input AND Gates with Inverted and Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

AND12, 16		12- and 16-Input AND Gates with Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

INV, 4, 8, 16		Single and Multiple Inverters
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MULT_AND		Fast Multiplier AND
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

NAND2-9		2- to 9-Input NAND Gates with Inverted and Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

NAND12, 16		12- and 16-Input NAND Gates with Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

NOR2-9		2- to 9-Input NOR Gates with Inverted and Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

NOR12, 16		12 and 16-Input NOR Gates with Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OAND2		2-Input AND Gate with Invertible Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ONAND2		2-Input NAND Gate with Invertible Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ONOR2		2-Input NOR Gate with Invertible Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OOR2		2-Input OR Gate with Invertible Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OR2-9		2- to 9-Input OR Gates with Inverted and Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OR12, 16		12- and 16-Input OR Gates with Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OXNOR2		2-Input Exclusive-NOR Gate with Invertible Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OXOR2		2-Input Exclusive-OR Gate with Invertible Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SOP3-4		Sum of Products
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

WAND1, 4, 8, 16		Open-Drain Buffers
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

WOR2AND		2-Input OR Gate with Wired-AND Open-Drain Buffer Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

XNOR2-9		2- to 9-Input XNOR Gates with Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

XOR2-9		2- to 9-Input XOR Gates with Non-Inverted Inputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

XORCY		XOR for Carry Logic with General Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

XORCY_D		XOR for Carry Logic with Dual Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

XORCY_L		XOR for Carry Logic with Local Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Map Elements

Map elements are used in conjunction with logic symbols to constrain the logic to particular CLBs or particular F or H function generators.

CLBMAP		Logic-Partitioning Control Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

F5MAP		5-Input Function Partitioning Control Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

FMAP		F Function Generator Partitioning Control Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

HMAP		H Function Generator Partitioning Control Symbol
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Memory Elements

The XC4000, Spartan, and SpartanXL architectures have a number of static RAM configurations defined as macros. In the Virtex and Spartan2 architectures, they are defined as primitives. These 16- or 32-word RAMs are 1, 2, 4, and 8 bits wide. There are two ROMs in the XC4000, Spartan and SpartanXL architectures, 16X1 and 32X1.

The Virtex and Spartan2 series have dedicated blocks of on-chip 4096-bit single-port and dual-port synchronous RAM. Each port is configured to a specific data width. There are five single-port block RAM primitives and 30 dual-port block RAM primitives.

RAM16X1		16-Deep by 1-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X1D		16-Deep by 1-Wide Static Dual Port Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X1D_1		16-Deep by 1-Wide Static Dual Port Synchronous RAM with Negative-Edge Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X1S		16-Deep by 1-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X1S_1		16-Deep by 1-Wide Static Synchronous RAM with Negative-Edge Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X2		16-Deep by 2-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X2D		16-Deep by 2-Wide Static Dual Port Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X2S		16-Deep by 2-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X4		16-Deep by 4-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X4D		16-Deep by 4-Wide Static Dual Port Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X4S		16-Deep by 4-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X8		16-Deep by 8-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X8D		16-Deep by 8-Wide Static Dual Port Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM16X8S		16-Deep by 8-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X1		32-Deep by 1-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X1S		32-Deep by 1-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X1S_1		32-Deep by 1-Wide Static Synchronous RAM with Negative-Edge Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X2		32-Deep by 2-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X2S		32-Deep by 2-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X4		32-Deep by 4-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X4S		32-Deep by 4-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X8		32-Deep by 8-Wide Static RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAM32X8S		32-Deep by 8-Wide Static Synchronous RAM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAMB4_Sn		4096-Bit Single-Port Synchronous Block RAM with Port Width (n) Configured to 1, 2, 4, 8, or 16 Bits (5 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

RAMB4_Sn_Sn		4096-Bit Dual-Port Synchronous Block RAM with Port Width (n) Configured to 1, 2, 4, 8, or 16 Bits (30 primitives)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ROM16X1		16-Deep by 1-Wide ROM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

ROM32X1		32-Deep by 1-Wide ROM
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Multiplexers

The multiplexer naming convention shown in the following figure indicates the number of inputs and outputs and if an enable is available. There are a number of TTL 7400-type multiplexers that have active-Low or inverted outputs.

Figure 2.7 Multiplexer Naming Convention

CY_MUX		2-to-1 Multiplexer for Carry Logic
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

F5_MUX		2-to-1 Lookup Table Multiplexer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M2_1		2-to-1 Multiplexer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M2_1B1		2-to-1 Multiplexer with D0 Inverted
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M2_1B2		2-to-1 Multiplexer with D0 and D1 Inverted
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M2_1E		2-to-1 Multiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M4_1E		4-to-1 Multiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M8_1E		8-to-1 Multiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

M16_1E		16-to-1 Multiplexer with Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXCY		2-to-1 Multiplexer for Carry Logic with General Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXCY_D		2-to-1 Multiplexer for Carry Logic with Dual Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXCY_L		2-to-1 Multiplexer for Carry Logic with Local Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXF5		2-to-1 Lookup Table Multiplexer with General Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXF5_D		2-to-1 Lookup Table Multiplexer with Dual Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXF5_L		2-to-1 Lookup Table Multiplexer with Local Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXF6		2-to-1 Lookup Table Multiplexer with General Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXF6_D		2-to-1 Lookup Table Multiplexer with Dual Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

MUXF6_L		2-to-1 Lookup Table Multiplexer with Local Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

OMUX2		2-to-1 Multiplexer
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_150		16-to-1 Multiplexer with Active-Low Enable and Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_151		8-to-1 Multiplexer with Active-Low Enable and Complementary Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_152		8-to-1 Multiplexer with Active-Low Output
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_153		Dual 4-to-1 Multiplexer with Active-Low Enables and Common Select Input
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_157		Quadruple 2-to-1 Multiplexer with Common Select and Active-Low Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_158		Quadruple 2-to-1 Multiplexer with Common Select, Active-Low Enable, and Active-Low Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_298		Quadruple 2-Input Multiplexer with Storage and Negative-Edge Clock
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_352		Dual 4-to-1 Multiplexer with Active-Low Enables and Outputs
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Shift Registers

Shift registers are available in a variety of sizes and capabilities. The naming convention shown in the following figure illustrates available features.

Figure 2.8 Shift Register Naming Convention

SR4CE, SR8CE, SR16CE		4-, 8-, 16-Bit Serial-In Parallel-Out Shift Registers with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SR4CLE, SR8CLE, SR16CLE		4-, 8-, 16-Bit Loadable Serial/Parallel-In Parallel-Out Shift Registers with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SR4CLED, SR8CLED, SR16CLED		4-, 8-, 16-Bit Shift Registers with Clock Enable and Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SR4RE, SR8RE, SR16RE		4-, 8-, 16-Bit Serial-In Parallel-Out Shift Registers with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SR4RLE, SR8RLE, SR16RLE		4-, 8-, 16-Bit Loadable Serial/Parallel-In Parallel-Out Shift Registers with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SR4RLED, SR8RLED, SR16RLED		4-, 8-, 16-Bit Shift Registers with Clock Enable and Synchronous Reset
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SRL16		16-Bit Shift Register Look-Up-Table (LUT)
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SRL16_1		16-Bit Shift Register Look-Up-Table (LUT) with Negative-Clock Edge
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SRL16E		16-Bit Shift Register Look-Up-Table (LUT) with Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

SRL16E_1		16-Bit Shift Register Look-Up-Table (LUT) with Negative-Edge Clock and Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_164		8-Bit Serial-In Parallel-Out Shift Register with Active-Low Asynchronous Clear
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_165S		8-Bit Loadable Serial/Parallel-In Parallel-Out Shift Register with Clock Enable
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_194		4-Bit Loadable Bidirectional Serial/Parallel-In Parallel-Out Shift Register
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

X74_195		4-Bit Loadable Serial/Parallel-In Parallel-Out Shift Register
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex

Shifters

Shifters are barrel shifters (BRLSHFT) of four and eight bits.

BRLSHFT4, 8		4-, 8-Bit Barrel Shifters
XC3000	XC4000E	XC4000X	XC5200	XC9000	Spartan	SpartanXL	Spartan2	Virtex