Altera Corporation
3–39
October 2007
Stratix II GX Device Handbook, Volume 2
Stratix II GX Dynamic Reconfiguration
Data Rate Switch Based on Clock Frequencies of Two PLLs
If your application requires the transceiver to switch between multiple
data rates, you can use channel reconfiguration to switch between the two
TX PLLs in the transceiver block. The following sections explain how to
setup two PLLs and achieve multiple data rates using channel
reconfiguration:
1.
Set the primary PLL (mode1) data rate setting.
2.
Set the local clock divider (if needed).
3.
Enable the
Channel Internals
option in the dynamic
reconfiguration section of the ALT2GXB (refer to
“Channel
Internals” on page 3–53
for more information).
4.
In
Channel Internals
option, enable the
use alternate reference
clock (Mode 2)
option.
●
Set all the parameters related to alternate PLL protocols, data
rates, bandwidth, and clock frequency.
5.
Set the
what is the logical reference index?
option (refer to the
Logical Reference Index).
6.
Set the core clocking options—transmit and receive
●
This is a mandatory step for every channel reconfiguration that
uses
tx_clkout
and
rx_clkout
(refer to
“Transmitter Core
Clocking” on page 3–45
).
7.
If there are no other settings to configure in the ALT2GXB, select
finish the ALT2GXB instantiation
.
8.
Lock down the input reference clocks pin placements (refer to Pin
Assignments).
9.
Compile and generate a MIF for Mode1 as primary and Mode2 as
alternate.
10. Similarly, generate a MIF for Mode2 as primary and Mode1 as
alternate by going through steps 1 through 9 again (refer to
“Example 1” on page 3–13
).