2–126
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
PLD-Transceiver Interface Clocking
The
Stratix II GX 0PPM Clock Group Driver Setting
can be made to any
of the transceiver output clocks (
tx_clkout
,
rx_clkout
, and
coreclk_out
) as well as any PLD clock input pins, transceiver
dedicated
REFCLK
pin, or PLD PLL output. User logic cannot be used as
a driver. As with the shared clock group setting, the driver setting for the
transceiver output clocks is made to the associated channel. For example,
for
tx_clkout
or
coreclk_out
, the transmitter channel name is
specified. For the
rx_clkout
being the driver, the receiver channel name
of the associated
rx_clkout
is specified. For the PLD input clock pins
and the transceiver
REFCLK
pins, the name of the clock pin can be
specified. For the PLL output, the PLL clock output port of the PLL can be
found in the node finder and entered as the driver name. An integer value
is specified for the group identification.
The
Stratix II GX 0 PPM Clock Group Setting
is made to the TX or RX
channel names.
A breakdown of the assignment in the assignment editor is shown in
Table 2–24
:
The following are examples of clocking configurations that can use the
0PPM assignment:
All RX channels are configured the same and one recovered clock is
feeding the
rx_coreclk
as shown in
Figure 2–101
. Though this example
shows all the RX channels reside in a transceiver block,
rx_clkout[0]
of this transceiver block can feed other RX channels of other transceiver
blocks. Note that this example is not showing any TX channels. If the
rx_clkout
is used as a driver, it can only feed RX channels. If these
channels are used in a duplex mode, the
tx_clkout
from the TX
channels should be used as the driver and feed the TX as well as the RX
phase compensation FIFOs. The
rx_clkout
cannot feed the
tx_coreclk
ports.
Table 2–24. Assignment Editor
To:
tx_dataout, rx_datain,
pld_clk_pin_name, refclk_pin,
and
pll_outclk
Assignment name:
Stratix II GX GXB 0 PPM Clock Group Driver Setting
Value:
1
To:
rx_datain[]
and
tx_dataout[]
Assignment name:
Stratix II GX GXB 0 PPM Clock Group Setting
Value:
1