Xilinx virtex-5 fpga

112 www.xilinx.com Virtex-5 FPGA User Guide
UG190 (v5.0) June 19, 2009
Chapter 3: Phase-Locked Loops (PLLs)
Table 3-9 shows the PLL attributes in Virtex-4 FPGA PMCD legacy mode.
Table 3-10 shows the PLL ports in Virtex-4 FPGA PMCD legacy mode.
CLKB1 CLKFBOUT
CLKC1 n/a
CLKD1 n/a
RST RST
REL REL
Table 3-8: Mapping of Port Names (Continued)
Virtex-4 FPGA
Port Name
Virtex-5 FPGA
Port Name
Table 3-9: PLL Attributes When in Virtex-4 FPGA PMCD Legacy Mode
Attribute Type Allowed Values Default Description
PLL_PMCD_MODE Boolean TRUE or FALSE FALSE Enables PLL to act as PMCDs
EN_REL Boolean TRUE or FALSE FALSE
When in PMCD mode (PLL_PMCD_MODE = TRUE),
specifies release of divided clock CLKA outputs when
the REL input pin is asserted.
RST_DEASSERT_CLK String
CLKA
CLKB
CLKA
When in PMCD mode (PLL_PMCD_MODE = TRUE),
specifies a clock to synchronize with the release of
RST.
Table 3-10: PLL Ports in Virtex-4 FPGA PMCD Legacy Mode
Port Name I/O Pin Description
CLKFB Input Virtex-4 FPGA PMCD legacy mode CLKB input clock to the PMCD.
CLKIN Input Virtex-4 FPGA PMCD legacy mode CLKA input clock to the PMCD.
RST Input
RST is the reset input to the Virtex-4 FPGA PMCD legacy mode. Asserting RST signal
asynchronously forces all outputs Low. Deasserting RST synchronously allows all
outputs to toggle.
REL Input
REL is the release input to the Virtex-4 FPGA PMCD legacy mode. Asserting the REL
signal releases the divided outputs synchronous to CLKA.
CLKOUT0 Output Virtex-4 FPGA PMCD legacy mode CLKB1.
CLKOUT1 Output Virtex-4 FPGA PMCD legacy mode CLKA1.
CLKOUT2 Output Virtex-4 FPGA PMCD legacy mode CLKA1D2.
CLKOUT3 Output Virtex-4 FPGA PMCD legacy mode CLKA1D4.
CLKOUT4 Output Virtex-4 FPGA PMCD legacy mode CLKA1D8.