Altera IP Compiler for PCI Express - Manual (Page 221)

August 2014 Altera Corporation IP Compiler for PCI Express User Guide
14. External PHYs
External PHY Support
This chapter discusses external PHY support, which includes the external PHYs and
interface modes shown in
Table 14–1 . The external PHY is not applicable to the hard
IP implementation.
When an external PHY is selected, additional logic required to connect directly to the
external PHY is included in the <variation name> module or entity.
The user logic must instantiate this module or entity in the design. The
implementation details for each of these modes are discussed in the following
sections.
16-bit SDR Mode
The implementation of this 16-bit SDR mode PHY support is shown in Figure 14–1
and is included in the file <variation name>.v or <variation name>.vhd and includes a
PLL. The PLL inclock is driven by refclk and has the following outputs:
Table 14–1. External PHY Interface Modes
PHY Interface Mode Clock Frequency Notes
16-bit SDR 125 MHz
In this the generic 16-bit PIPE interface, both the TX and
RX
data are clocked by the refclk input which is the pclk
from the PHY.
16-bit SDR mode (with source
synchronous transmit clock)
125 MHz
This enhancement to the generic PIPE interface adds a
TXClk
to clock the TXData source synchronously to the
external PHY. The TIXIO1100 PHY uses this mode.
8-bit DDR 125 MHz
This double data rate version saves I/O pins without
increasing the clock frequency. It uses a single refclk input
(which is the pclk from the PHY) for clocking data in both
directions.
8-bit DDR mode (with 8-bit DDR source
synchronous transmit clock)
125 MHz
This double data rate version saves I/O pins without
increasing the clock frequency. A TXClk clocks the data
source synchronously in the transmit direction.
8-bit DDR/SDR mode (with 8-bit DDR
source synchronous transmit clock)
125 MHz
This is the same mode as 8-bit DDR mode except the
control signals rxelecidle, rxstatus, phystatus, and
rxvalid
are latched using the SDR I/O register rather
than the DDR I/O register. The TIXIO1100 PHY uses this
mode.
8-bit SDR 250 MHz
This is the generic 8-bit PIPE interface. Both the TX and RX
data are clocked by the refclk input which is the pclk from
the PHY. The NXP PX1011A PHY uses this mode.
8-bit SDR mode (with Source
Synchronous Transmit Clock)
250 MHz
This enhancement to the generic PIPE interface adds a
TXClk
to clock the TXData source synchronously to the
external PHY.
August 2014