XC4VFX40-10FFG1152C Xilinx Inc, XC4VFX40-10FFG1152C Datasheet - Page 36

• Manufacturer Part Number: XC4VFX40-10FFG1152C
• Description: IC FPGA VIRTEX-4 FX 40K 1152FBGA
• Manufacturer: Xilinx Inc
• Series: Virtex™-4r

Specifications of XC4VFX40-10FFG1152C

• Number Of Logic Elements/cells: 41904
• Number Of Labs/clbs: 4656
• Total Ram Bits: 2654208
• Number Of I /o: 448
• Voltage - Supply: 1.14 V ~ 1.26 V
• Mounting Type: Surface Mount
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 1152-BBGA, FCBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of Gates: -

Chapter 1: Clock Resources
36
Additional Use Models
Asynchronous Mux Using BUFGCTRL
In some cases an application requires immediate switching between clock inputs or
bypassing the edge sensitivity of BUFGCTRL. An example is when one of the clock inputs
is no longer switching. If this happens, the clock output would not have the proper
switching conditions because the BUFGCTRL never detected a clock edge. This case uses
the asynchronous mux.
design example.
In
•
•
•
•
Figure
The current clock is from I0.
S is activated High.
The Clock output immediately switches to I1.
When Ignore signals are asserted High, glitch protection is disabled.
Figure 1-13: Asynchronous Mux with BUFGCTRL Design Example
1-14:
I1
I0
O
I1
I0
Asynchronous MUX
S
S
Figure 1-14
Design Example
Figure 1-14: Asynchronous Mux Timing Diagram
at I0
Figure 1-13
www.xilinx.com
shows the asynchronous mux timing diagram.
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illustrates an asynchronous mux with BUFGCTRL
S
Begin I1
V
V
V
V
DD
DD
DD
DD
IGNORE1
CE1
S1
I1
I0
S0
CE0
IGNORE0
T
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ug070_1_13_082704
UG070 (v2.6) December 1, 2008
UG070_1_14_033005
Virtex-4 FPGA User Guide
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