2–148
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Native Modes
Figures 2–111
and
2–112
show examples of legal and illegal transceiver
placements with respect to the Basic single-width mode with ×4 clocking
enabled.
Figure 2–111. Examples of Legal Transceiver Placement
Figure 2–112. Examples of Illegal Transceiver Placement
Clocking and Reset Recommendations
To minimize the transmitter channel to channel skew across transceiver
blocks, Altera recommends:
■
Using the dedicated
REFCLK
pins of the centrally located transceiver
block in your design to provide the input reference clock for all
transceiver blocks. This reduces the skew on the input reference
clock driving the CMU PLL in each transceiver block. For example,
in a design with 12 channels placed across Banks 13, 14, and 15, use
the
REFCLK
pins of Bank 14 to provide the input reference clock. In a
design with 16 channels placed across Banks 13, 14, 15, and 16, use
the
REFCLK
pins of either Bank 14 or 15.
■
De-asserting the
tx_digitalreset
signal of all used transceiver
blocks simultaneously after
pll_locked
signal from all active
transceiver blocks goes high.
Ch0
Ch1
Ch2
Ch3
Ch0
Ch1
Ch2
Ch3
Basic Single-Width mode with x4
clocking option
enabled
Basic Single-Width mode with x4
clocking option
enabled
Unused Channel
Unused Channel
Serial RapidIO
Serial RapidIO
Basic Single-Width mode with x4
clocking option
disabled
Basic Single-Width mode with x4
clocking option
disabled
Ch0
Ch1
Ch2
Ch3
Ch0
Ch1
Ch2
Ch3
Basic Single-Width mode with x4
clocking option
enabled
Basic Single-Width mode with x4
clocking option
enabled
Serial RapidIO
Serial RapidIO
Basic Single-Width mode with x4
clocking option
disabled
Basic Single-Width mode with x4
clocking option
disabled
Basic Single-Width mode with x4
clocking option
enabled
Basic Single-Width mode with x4
clocking option
enabled