3–106
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Channel and Clock Multiplier Unit (CMU) PLL Reconfiguration
When you configure a transceiver channel in the ALT2GXB MegaWizard,
Altera recommends that you keep track of the TX PLL that drives the
channel. You may require this information when you want to reconfigure
the TX PLLs dynamically. This is illustrated in
“Design Examples” on
page 3–121
.
1
The
logical_tx_pll_sel
port does not modify any
transceiver setting on the RX side.
Figure 3–51
shows the required signal transitions to reconfigure the
TX PLL with a
logical_tx_pll
value of
1
. Keep the
logical_tx_pll_sel
and
logical_tx_pll_sel_en
signals at a
constant logic level until the reconfig controller asserts the
channel_reconfig_done
signal.
Figure 3–51. Signal Transitions of the logical_tx_pll_sel and logical_tx_pll_sel_en Ports
enabled
not enabled
value on the
logical_tx_pll_sel
port.
not enabled
not enabled
logical
tx pll value
stored in
the MIF.
Table 3–11. logical_tx_pll_sel and logical_tx_pll_en Combinations (Part 2
of 2)
logical_tx_pll_sel
Port
logical_tx_pll_se_en
Port
Selected logical tx pll Value by
the Reconfig Controller
101
logical_tx_pll_sel_en
reconfig controller does not
register the logical_tx_pll_sel
value for this write since the
logical_tx_pll_sel_en is low
logical_tx_pll_sel
write_all
channel_reconfig_done
reconfig_mode_sel