XQ2V3000 Xilinx, XQ2V3000 Datasheet - Page 26

• Manufacturer Part Number: XQ2V3000
• Description: QPro Virtex-II 1.5V Military QML Platform FPGAs
• Manufacturer: Xilinx

QPro Virtex-II 1.5V Military QML Platform FPGAs
3-State Buffers
Introduction
Each Virtex-II CLB contains two 3-state drivers (TBUFs)
that can drive on-chip buses. Each 3-state buffer has its
own 3-state control pin and its own input pin.
Each of the four slices have access to the two 3-state buff-
ers through the switch matrix, as shown in
TBUFs in neighboring CLBs can access slice outputs by
direct connects. The outputs of the 3-state buffers drive hor-
izontal routing resources used to implement 3-state buses.
CLB/Slice Configurations
Table 16
the CLBs are identical and each CLB or slice can be imple-
Table 16: Logic Resources in One CLB
26
Slices
4
summarizes the logic resources in one CLB. All of
Figure 28: Virtex-II 3-State Buffers
Switch
Matrix
LUTs
8
Flip-Flops
Slice
Slice
S1
S0
TBUF
TBUF
Figure 29: 3-State Buffer Connection to Horizontal Lines
8
Switch
matrix
CLB-II
DS031_37_060700
Slice
Slice
S3
S2
MULT_ANDs
8
Figure
Programmable
connection
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28.
Carry Chains
Arithmetic &
The 3-state buffer logic is implemented using AND-OR logic
rather than 3-state drivers, so that timing is more predict-
able and less load dependent especially with larger devices.
Locations/Organization
Four horizontal routing resources per CLB are provided for
on-chip 3-state buses. Each 3-state buffer has access alter-
nately to two horizontal lines, which can be partitioned as
shown in
SelectRAM memory and multiplier or I/O blocks are
skipped.
Number of 3-State Buffers
Table 15
each Virtex-II device. The number of 3-state buffers is twice
the number of CLB elements.
Table 15: Virtex-II 3-State Buffers
mented in one of the configurations listed.
the available resources in all CLBs.
2
XQ2V1000
XQ2V3000
XQ2V6000
Switch
matrix
CLB-II
Device
shows the number of 3-state buffers available in
Figure
Chains
SOP
2
29. The switch matrices corresponding to
3-State Buffers
Distributed
SelectRAM
per Row
128 bits
DS031_09_032700
3 - state lines
112
176
64
DS122 (v1.1) January 7, 2004
Registers
Product Specification
of 3-State Buffers
128 bits
Shift
Total Number
Table 17
16,896
2,560
7,168
TBUF
shows
2
R