HC4GX15 Datasheet, PDF (538/668 Pages) Altera Corporation – HardCopy IV Device Handbook

2–80
Chapter 2: HardCopy IV GX Dynamic Reconfiguration
Description of Transceiver Channel Reconfiguration Modes
Table 2–26. Transmitter Core Clocking (Part 2 of 2)
■ Enable this option if you want tx_clkout of the
first channel (channel 0) of the transceiver block to
provide the write clock to the Transmitter Phase
Compensation FIFOs of the remaining channels in
the transceiver block.
■ This option is typically enabled when all the
channels of a transceiver block are of the same
functional mode and data rate, and are
reconfigured to the identical functional mode and
data rate.
■ Consider the following scenario:
Four regular transceiver channels configured at
3 Gbps and in the same functional mode.
Channel and CMU PLL Reconfiguration mode is
enabled in the ALTGX_RECONFIG MegaWizard
Plug-In Manager.
You want to reconfigure all four regular
transceiver channels to 1.5 Gbps and vice
versa.
■ Option 1 is applicable in this scenario because it
saves clock resources.
■ Figure 2–40 shows the sharing of channel 0's
tx_clkout between all four regular channels of
a transceiver block.
■ Enable this option if you want the individual transmitter channel
tx_clkout signals to provide the write clock to their
respective Transmit Phase Compensation FIFOs.
■ This option is typically enabled when each transceiver channel is
reconfigured to a different functional mode using channel
reconfiguration.
■ Consider the following scenario:
Four regular transceiver channels configured at 3 Gbps and
different functional modes.
Channel and CMU PLL Reconfiguration mode is enabled in the
ALTGX_RECONFIG MegaWizard Plug-In Manager.
You want to reconfigure each of the four regular transceiver
channels to different data rates and different functional
modes.
■ Option 2 is applicable in this scenario because the design
requires all four regular transceiver channels to be reconfigured
to different data rates and functional modes.
■ Figure 2–41 shows how each transmitter channel's
tx_clkout signal provides a clock to the Transmit Phase
Compensation FIFOs of the respective transceiver channels.
■ Therefore, each channel can be reconfigured to a different
functional mode using the Channel and CMU PLL
Reconfiguration mode.
Note to Table 2–26:
(1) The Reconfig 2 screen is not available for PMA-only channels (channels configured in Basic [PMA Direct] ×1 and ×N modes).
HardCopy IV Device Handbook, Volume 3
© June 2009 Altera Corporation