3–104
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Channel and Clock Multiplier Unit (CMU) PLL Reconfiguration
option, is useful to switch the TX channel to multiple data rates. When the
transmit side is using one TX PLL, reconfigure the second TX PLL using
the TX PLL Reconfiguration feature. Then, use the channel
reconfiguration with TX PLL select feature to switch the logical TX PLL
select multiplexer to listen to the reconfigured TX PLL. This feature may
require you to use the optional
logical_tx_pll_sel
port available in
the
ALT2GXB RECONFIG
tab. The function of this port is explained in
“Logical TX PLL” on page 3–98
.
Consider the same example mentioned in
“Channel and TX PLL
Reconfiguration” on page 3–100
(refer to
Figure 3–46
for conditions
before reconfiguration).
Figure 3–49
shows the reconfigured functional
blocks after the mode1 MIF write is completed. Note that the TX PLLs are
not reconfigured. Since the new MIF has the same functional blocks as the
original configuration, there is no change in the functional blocks or the
data rate in the transmit side after reconfiguration. Note that the MIF
configures the RX PLL to 6.25 Gbps.
Figure 3–49. Reconfigured Functional Blocks After Channel and TX PLL Select Reconfiguration
/1
clock
mux
clock
mux
pll_inclk_rx_cruclk[1]
156.25 MHz
125 MHz
pll_inclk_rx_cruclk[0]
Clock Multiplier Unit
5 Gbps
LOGICAL
TXPLL0
2.5 Gbps
LOGICAL
TXPLL1
clock
MUX
RX CHANNEL
6.25 Gbps
RX PLL
6.25 Gbps
d analog logic
Full Duplex Transceiver Channel
TX CHANNEL
Logical
TX PLL
Select
LOCAL
DIVIDER
5 Gbps
d analog logic
Reconfigured functional blocks after MIF write