XC2V8000-5BF957C Xilinx, Inc., XC2V8000-5BF957C Datasheet - Page 33

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

Virtex-II 1.5V Field-Programmable Gate Arrays
Total Amount of SelectRAM Memory
Table 19
available for each Virtex-II device. The 18-Kbit SelectRAM
blocks are cascadable to implement deeper or wider single- or
dual-port memory resources.
Table 19: Virtex-II SelectRAM Memory Available
18-Bit x 18-Bit Multipliers
Introduction
A Virtex-II multiplier block is an 18-bit by 18-bit 2’s comple-
ment signed multiplier. Virtex-II devices incorporate many
embedded multiplier blocks. These multipliers can be asso-
ciated with an 18-Kbit block SelectRAM resource or can be
used independently. They are optimized for high-speed
operations and have a lower power consumption compared
to an 18-bit x 18-bit multiplier in slices.
Each SelectRAM memory and multiplier block is tied to four
switch matrices, as shown in
Module 2 of 4
26
XC2V1000
XC2V1500
XC2V2000
XC2V3000
XC2V4000
XC2V6000
XC2V8000
XC2V250
XC2V500
XC2V40
XC2V80
Device
shows the amount of block SelectRAM memory
Blocks
120
144
168
24
32
40
48
56
96
4
8
Total SelectRAM Memory
Figure
in Kbits
1,008
1,728
2,160
2,592
3,024
144
432
576
720
864
72
34.
1,032,192
1,769,472
2,211,840
2,654,208
3,096,576
147,456
442,368
589,824
737,280
884,736
in Bits
73,728
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1-800-255-7778
Association With Block SelectRAM Memory
The interconnect is designed to allow SelectRAM memory
and multiplier blocks to be used at the same time, but some
interconnect is shared between the SelectRAM and the
multiplier. Thus, SelectRAM memory can be used only up to
18 bits wide when the multiplier is used, because the multi-
plier shares inputs with the upper data bits of the
SelectRAM memory.
This sharing of the interconnect is optimized for an
18-bit-wide block SelectRAM resource feeding the multi-
plier. The use of SelectRAM memory and the multiplier with
an accumulator in LUTs allows for implementation of a digi-
tal signal processor (DSP) multiplier-accumulator (MAC)
function, which is commonly used in finite and infinite
impulse response (FIR and IIR) digital filters.
Configuration
The multiplier block is an 18-bit by 18-bit signed multiplier
(2's complement). Both A and B are 18-bit-wide inputs, and
the output is 36 bits.
A[17:0]
B[17:0]
Figure 34: SelectRAM and Multiplier Blocks
Switch
Switch
Switch
Switch
Matrix
Matrix
Matrix
Matrix
Figure 35: Multiplier Block
Figure 35
MULT 18 x 18
Multiplier Block
18-Kbit block
SelectRAM
DS031-2 (v1.8) October 12, 2001
Advance Product Specification
shows a multiplier block.
DS031_40_100400
DS031_33_101000
P[35:0]
R