Command Register (Cmd) - Xilinx Virtex-4 Configuration User Manual

Chapter 7: Configuration Details
Table 7-5: Configuration Registers (Continued)

Command Register (CMD)

The Command Register is used to instruct the configuration control logic to strobe global
signals and perform other configuration functions. The command present in the CMD
register is executed each time the FAR is loaded with a new value.
Command Register commands and codes.
Table 7-6: Command Register Codes
90
Reg. Name Read/Write Address
Read/Write
MASK
STAT Read
Write
LOUT
COR Read/Write
Write
MFWR
CBC Write
Read/Write
IDCODE
AXSS Read/Write
Command Code
NULL 0000 Null Command
Write Configuration Data: used prior to writing configuration data to
WCFG 0001
the FDRI.
Multiple Frame Write: used to perform a write of a single frame data to
MFWR 0010
multiple frame addresses.
Last Frame: Deasserts the GHIGH_B signal, activating all interconnect.
LFRM 0011
The GHIGH_B signal is asserted with the AGHIGH command.
Read Configuration Data: used prior to reading configuration data
RCFG 0100
from the FDRO.
Begin Startup Sequence: initiates the startup sequence. The startup
START 0101 sequence begins after a successful CRC check and a DESYNC
command are performed.
Reset Capture: resets the CAPTURE signal after performing readback-
RCAP 0110
capture in single-shot mode (see
RCRC 0111 Reset CRC: resets the CRC register
Assert GHIGH_B Signal: places all interconnect in a high-Z state to
prevent contention when writing new configuration data. This
AGHIGH 1000
command is only used in shutdown reconfiguration. Interconnect is
reactivated with the LFRM command.
Switch CCLK Frequency: updates the frequency of the Master CCLK to
SWITCH 1001
the value specified by the OFSEL bits in the COR.
Pulse the GRESTORE Signal: sets/resets (depending on user
GRESTORE 1010
configuration) IOB and CLB flip-flops.
Begin Shutdown Sequence: initiates the shutdown sequence, disabling
SHUTDOWN 1011 the device when finished. Shutdown activates on the next successful
CRC check or RCRC instruction (typically an RCRC instruction).
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Masking Register for CTL
00110
Status Register
00111
Legacy Output Register (DOUT for daisy chain)
01000
Configuration Option Register
01001
Multiple Frame Write
01010
Initial CBC value register
01011
Device ID register
01100
User bitstream access register
01101
Description
"Readback Capture," page
Virtex-4 FPGA Configuration User Guide
Description
Table 7-6 gives the
113).
UG071 (v1.12) June 2, 2017
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