Dynamic Reconfiguration Ready Output - Drdy - Xilinx Virtex-5 FPGA User Manual

Table 2-4: DCM Status Mapping to DO Bus (Continued)
When LOCKED is Low (during reset or the locking process), all the status signals are
deasserted Low.

Dynamic Reconfiguration Ready Output - DRDY

The dynamic reconfiguration ready (DRDY) output pin provides the response to the DEN
signal for the DCM's dynamic reconfiguration feature. Further information on the DRDY
pin is available in the dynamic reconfiguration section in the Virtex-5 FPGA Configuration
Guide.
Virtex-5 FPGA User Guide
UG190 (v5.0) June 19, 2009
DO Bit Status
DO[3] CLKFB stopped
DO[15:4] Not assigned
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Description
Asserted when the feedback clock is stopped (CLKFB
remains High or Low for one or more clock cycles). The
DO[3] CLKFB stopped status is asserted within six
CLKIN cycles after CLKFB is stopped. CLKFB stopped
will deassert within six CLKIN cycles when CLKFB
resumes after being stopped momentarily. An
occasionally skipped CLKFB does not affect the DCM
operation. However, stopping CLKFB for a long time
can result in the DCM losing LOCKED. When LOCKED
is lost, the DCM needs to be reset to resume operation.
When the DLL portion of the DCM is not used (for
example, when using CLKFX output only), the CLKFB
can be left unconnected. In this case, DO[3] is
deasserted.
DCM Ports
57