Xilinx Virtex-4 Configuration User Guide

Virtex-4 FPGA Configuration User Guide www.xilinx.com 19
UG071 (v1.12) June 2, 2017
Bitstream Loading (Steps 4-7)
R
the device to upcoming configuration data and aligns the configuration data with the
internal configuration logic. Any data on the configuration input pins prior to
synchronization is ignored.
Synchronization is transparent to most users because all configuration bitstreams (.bit
files) generated by the Xilinx ISE® Bitstream Generator (BitGen) software include the
synchronization word. Table 1-5 shows signals relating to synchronization.
Check Device ID (Step 5)
Once the device is synchronized, a device ID check must pass before the configuration data
frames can be loaded. This prevents an attempted configuration with a bitstream that is
formatted for a different device.
For example, the device ID check should prevent an XC4VLX15 from being configured
with an XC4VLX80 bitstream.
The device ID check is built into the bitstream, making this step transparent to most
designers. Figure 1-7 shows the relative position of the device ID check, Table 1-6 shows
the Virtex-4 device IDs, and Table 1-7 shows the signals relating to the device ID check. The
device ID check is performed through commands in the bitstream to the configuration
logic, not through the JTAG IDCODE register in this case.
Table 1-5: Signals Relating to Synchronization
Signal Name Type Access Description
DALIGN Status Only available through the
SelectMAP interface during an
ABORT. (See “Configuration
Abort Sequence Description,”
page 49.)
Indicates whether device
is synchronized.
Figure 1-7: Check Device ID (Step 5)
Table 1-6: Virtex-4 Device ID Codes
Device IDCODE Device IDCODE Device IDCODE
XC4VLX15 01658093 XC4VFX12 01E58093
XC4VLX25 0167C093 XC4VSX25 02068093 XC4VFX20 01E64093
XC4VLX40 016A4093 XC4VSX35 02088093 XC4VFX40 01E8C093
(1)
XC4VLX60 016B4093 XC4VSX55 020B0093 XC4VFX60 01EB4093
XC4VLX80 016D8093
XC4VLX100 01700093 XC4VFX100 01EE4093
XC4VLX160 01718093 XC4VFX140 01F14093
Device
Power-Up
Sample Mode
Pins
Synchronization
Device ID
Check
CRC Check
Clear
Configuration
Memory
Startup
Sequence
Load
Configuration
Data
Start
Finish
ug071_07_122105
Bitstream
Loading
Steps
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Xilinx Virtex-4 Specifications

General

Brand	Xilinx
Model	Virtex-4
Category	Motherboard
Language	English