User guide

38 www.xilinx.com Virtex-5 FPGA Integrated Endpoint Block
UG197 (v1.5) July 22, 2009
Chapter 2: Integrated Endpoint Block Functionality
R
performing the final Management write to the attribute address. This must be done to
allow the new values to propagate within the integrated Endpoint block. The reset port(s)
should be asserted for an additional four
CRMUSERCLK cycles after the final assertion of
MGMTWREN (see Figure 2-10). The exact port(s) that must be asserted to reset the block
(indicated by “reset” in the timing diagram) depends on the reset mode. When
RESETMODE =FALSE, the CRMNVRSTN port should be asserted as shown in the timing
diagram (Figure 2-10). When
RESETMODE = TRUE, all reset ports other than
CRMMGMTRSTN should be asserted.
Reset
All the flip-flops in the Management Interface have their asynchronous reset input driven
by the
CRMMGMTRSTN port. Integrated Endpoint block logic ensures that this reset is
synchronously deasserted with respect to core_clk. Separating the management reset
allows the user to reset the rest of the block without resetting the management interface.
Attribute values such as
DEVICEID or VENDORID that were previously written through the
management interface are retained, even when other parts of the integrated Endpoint
block are reset (because of link down, soft reset, etc.). If the user desires to override the
attribute definitions for attributes such as
DEVICEID and VENDORID, they only need to be
written once at power-on.
Ports
Table 2-7 shows the ports of the Management interface.
Figure 2-10: Management Interface Write Timing
CRMUSERCLK
MGMTADDR[10:0]
MGMTBWREN[3:0]
Active-Low Reset
(see above)
MGMTWDATA[31:0]
MGMTWREN
A0
D0
BWR0
UG197_c2_08_082406
Table 2-7: Management Interface Ports
Port Direction
Clock
Domain
Description
MGMTRDATA[31:0]
Output user_clk Management Interface read data.
MGMTWDATA[31:0]
Input user_clk Management Interface write data.
MGMTBWREN[3:0]
Input user_clk Management Interface byte write enables.
MGMTWREN
Input user_clk Management Interface write enable.
MGMTADDR[10:0]
Input user_clk Management Interface address.
MGMTRDEN
Input user_clk Management Interface read enable.