
Chapter 8: PHY IP Core for PCI Express (PIPE) 8–11
Optional Status Interface
November 2012 Altera Corporation Altera Transceiver PHY IP Core
User Guide
Table 8–7 lists the pipe_pclk frequencies for all available PCS interface widths.
Doubling the FPGA transceiver width haves the required frequency.
Optional Status Interface
Table 8–8 describes the signals the optional status signals.
fixedclk
Input
A 100 MHz or 125 MHz clock used for the receiver detect circuitry.
This clock can be derived from
pll_ref_clk
.
pipe_pclk
Output
Generated in the PMA and driven to the MAC PHY interface. All data
and status signals are synchronous to pipe_pclk. This clock has the
following frequencies:
■ Gen1: 62.5 MHz
■ Gen2:125 MHz
■ Gen3: 250 MHz
Table 8–6. Clock Ports
Signal Name Direction Description
Table 8–7. pipe_pclk Frequencies
Capability FPGA Transceiver Width Gen1 Gen2 Gen3
Gen1 only
8 bits 250 MHz — —
16 bits 125 MHz — —
Gen2 capable 16 bits 125 MHz 250 MHz —
Gen3 capable 32 bits 62.5 MHz 125 MHz 250MHz
Table 8–8. Status Signals
(1)
Signal Name Direction Signal Name
tx_ready
Output
When asserted, indicates that the TX interface has exited the reset
state and is ready to transmit.
rx_ready
Output
When asserted, indicates that the RX interface has exited the reset
state and is ready to receive.
pll_locked[
<
p
>
-1:0]
Output
When asserted, indicates that the TX PLL is locked to the input
reference clock. This signal is asynchronous.
rx_is_lockedtodata[<n>-1:0]
Output
When asserted, the receiver CDR is in to lock-to-data mode. When
deasserted, the receiver CDR lock mode depends on the
rx_locktorefclk
signal level.
rx_is_lockedtoref[<n>-1:0]
Output
Asserted when the receiver CDR is locked to the input reference clock.
This signal is asynchronous.
rx_syncstatus[<d><n>/8-1:0]
Output
Indicates presence or absence of synchronization on the RX interface.
Asserted when word aligner identifies the word alignment pattern or
synchronization code groups in the received data stream.
rx_signaldetect[<d><n>/8-
1:0]
Output
When asserted indicates that the lane detects a sender at the other
end of the link.
Note to Table 8–8:
(1) <n> is the number of lanes. <d> is the deserialization factor. <p> is the number of PLLs.
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