3–84
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Channel and PMA Controls Reconfiguration
4.
In the
Reconfig
tab, select
Analog controls
if you wish to modify
the PMA values dynamically (V
OD
, pre-emphasis, DC gain, and
equalization).
5.
Select the
Channel internals
and
Use Alternate reference clock
options. These options must be selected since Basic mode 2 requires
a different input clock frequency.
6.
Set the
protocol
option to
Basic
, set the data rate to
2.000 Gbps
, and
set the
input clock frequency
option to
125 MHz
. For this example,
since both the configurations have the same PLD interface width
and functional blocks (
Table 3–7
), you do not need the
Channel
interface
option.
7.
In the
Reconfig 2
tab, select the
Use respective receiver core clocks
and
Use respective transmitter core clocks
options (row 6,
Table 3–7
).
8.
Complete the ALT2GXB MegaWizard instantiation.
Section II—Control Logic for the RECONFIG Controller:
Follow the same procedure as described in
“Example 1—Configuring a
Transceiver Channel Between GIGE Mode and SONET/SDH OC48
Mode” on page 3–72
.
Section III—Logic for the Basic Mode 1 and Basic Mode 2 Datapath:
Clock the data to the transceiver with the
tx_clkout
signal on the
transmitter side for both configurations. Similarly, for the receive side,
clock the data from the transceiver with the
rx_clkout
signal for both
configurations. A single logic block can handle data processing when the
transceiver channel is configured between these two modes.
Section IV—Reset and Control Logic:
Follow the same procedure as described in
“Example 1—Configuring a
Transceiver Channel Between GIGE Mode and SONET/SDH OC48
Mode” on page 3–72
.
Example 3: Dynamic Rate Switch for the Transmit Side Design Example
This design example explains the steps to dynamically divide the
transmit data rate of a transceiver channel by 4, 2, or 1 without requiring
MIF generation. The ALT2GXB_RECONFIG instance provides a
rate_switch_ctrl
signal for this purpose.