XC2V8000-5BF957C Xilinx, Inc., XC2V8000-5BF957C Datasheet - Page 24

• Manufacturer Part Number: XC2V8000-5BF957C
• Description: Virtex-II 1.5V Field-Programmable Gate Array
• Manufacturer: Xilinx, Inc.

Multiplexers
Virtex-II function generators and associated multiplexers
can implement the following:
•
•
•
•
Fast Lookahead Carry Logic
Dedicated carry logic provides fast arithmetic addition and
subtraction. The Virtex-II CLB has two separate carry
chains, as shown in the
The height of the carry chains is two bits per slice. The carry
chain in the Virtex-II device is running upward. The dedi-
cated carry path and carry multiplexer (MUXCY) can also
DS031-2 (v1.8) October 12, 2001
Advance Product Specification
4:1 multiplexer in one slice
8:1 multiplexer in two slices
16:1 multiplexer in one CLB element (4 slices)
32:1 multiplexer in two CLB elements (8 slices)
R
G
G
F
F
Figure
23.
Figure 22: MUXF5 and MUXFX multiplexers
Slice S3
Slice S2
Slice S1
Slice S0
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G
G
F
F
Each Virtex-II slice has one MUXF5 multiplexer and one
MUXFX multiplexer. The MUXFX multiplexer implements
the MUXF6, MUXF7, or MUXF8, as shown in
Each CLB element has two MUXF6 multiplexers, one
MUXF7 multiplexer and one MUXF8 multiplexer. Examples
of multiplexers are shown in the Virtex-II User Guide. Any
LUT can implement a 2:1 multiplexer.
be used to cascade function generators for implementing
wide logic functions.
Arithmetic Logic
The arithmetic logic includes an XOR gate that allows a
2-bit full adder to be implemented within a slice. In addition,
a dedicated AND (MULT_AND) gate (shown in
improves the efficiency of multiplier implementation.
CLB
Virtex-II 1.5V Field-Programmable Gate Arrays
MUXF8 combines
the two MUXF7 outputs
(Two CLBs)
MUXF6 combines the two MUXF5
outputs from slices S2 and S3
MUXF7 combines the two MUXF6
outputs from slices S0 and S2
MUXF6 combines the two MUXF5
outputs from slices S0 and S1
DS031_08_100201
Module 2 of 4
Figure
Figure
15)
22.
17