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Virtex-II Platform FPGAs: Detailed Description
R
DS031-2 (v3.0) August 1, 2003
Product Specification
1-800-255-7778Module 2 of 4
21
18 Kbit Block SelectRAM
Resources
Introduction
Virtex-II devices incorporate large amounts of 18 Kbit block
SelectRAM. These complement the distributed SelectRAM
resources that provide shallow RAM structures imple-
mented in CLBs. Each Virtex-II block SelectRAM is an 18
Kbit true dual-port RAM with two independently clocked and
independently controlled synchronous ports that access a
common storage area. Both ports are functionally identical.
CLK, EN, WE, and SSR polarities are defined through con-
figuration.
Each port has the following types of inputs: Clock and Clock
Enable, Write Enable, Set/Reset, and Address, as well as
separate Data/parity data inputs (for write) and Data/parity
data outputs (for read).
Operation is synchronous; the block SelectRAM behaves
like a register. Control, address and data inputs must (and
need only) be valid during the set-up time window prior to a
rising (or falling, a configuration option) clock edge. Data
outputs change as a result of the same clock edge.
Configuration
The Virtex-II block SelectRAM supports various configura-
tions, including single- and dual-port RAM and various
data/address aspect ratios. Supported memory configura-
tions for single- and dual-port modes are shown in
Table 13
.
Table 11:
Logic Resources in One CLB
Slices
LUTs
Flip-Flops
MULT_ANDs
Arithmetic &
Carry-Chains
SOP
Chains
Distributed
SelectRAM
Shift
Registers
TBUF
4
8
8
8
2
2
128 bits
128 bits
2
Table 12:
Virtex-II Logic Resources Available in All CLBs
Device
CLB Array:
Row x
Column
Number
of
Slices
Number
of
LUTs
Max Distributed
SelectRAM or Shift
Register (bits)
Number
of
Flip-Flops
Number
of
Carry-Chains
(1)
Number
of SOP
Chains
(1)
XC2V40
8 x 8
256
512
8,192
512
16
16
XC2V80
16 x 8
512
1,024
16,384
1,024
16
32
XC2V250
24 x 16
1,536
3,072
49,152
3,072
32
48
XC2V500
32 x 24
3,072
6,144
98,304
6,144
48
64
XC2V1000
40 x 32
5,120
10,240
163,840
10,240
64
80
XC2V1500
48 x 40
7,680
15,360
245,760
15,360
80
96
XC2V2000
56 x 48
10,752
21,504
344,064
21,504
96
112
XC2V3000
64 x 56
14,336
28,672
458,752
28,672
112
128
XC2V4000
80 x 72
23,040
46,080
737,280
46,080
144
160
XC2V6000
96 x 88
33,792
67,584
1,081,344
67,584
176
192
XC2V8000
112 x 104
46,592
93,184
1,490,944
93,184
208
224
Notes:
1.
The carry-chains and SOP chains can be split or cascaded.
Table 13:
Dual- and Single-Port Configurations
16K x 1 bit
2K x 9 bits
8K x 2 bits
1K x 18 bits
4K x 4 bits
512 x 36 bits