HC4GX15 Datasheet, PDF (461/668 Pages) Altera Corporation – HardCopy IV Device Handbook

Chapter 2: HardCopy IV GX Dynamic Reconfiguration
2–3
Dynamic Reconfiguration Modes
Dynamic Reconfiguration Modes
The different modes of dynamic reconfiguration are as follows:
■ Offset cancellation for receiver channels
■ PMA controls reconfiguration
■ Transceiver channel reconfiguration
1 Offset cancellation for receiver channels mode and PMA controls reconfiguration
mode are the same for both the regular transceiver channels and PMA-only channels.
These modes are described briefly in the following sections.
Offset Cancellation
The HardCopy IV GX device provides an offset cancellation circuit per receiver
channel to counter the offset variations due to process, voltage, and temperature
(PVT). These variations create an offset in the analog circuit voltages, pushing them
out of the expected range. In addition to reconfiguring the transceiver channel, the
dynamic reconfiguration controller performs offset cancellation on all receiver
channels connected to it on power up.
The Offset cancellation for Receiver channels option is automatically enabled in
both the ALTGX and ALTGX_RECONFIG MegaWizard Plug-In Managers for
Receiver and Transmitter and Receiver only configurations. It is not available for
Transmitter only configurations. For Receiver and Transmitter and Receiver only
configurations, you must connect the necessary interface signals between the
ALTGX_RECONFIG and ALTGX (with receiver channels) instances. For more
information, refer to “Offset Cancellation Control for Receiver Channels” on
page 2–43.
1 For proper device operation, you must always connect the ALTGX_RECONFIG and
ALTGX (with receiver channels) instances.
PMA Controls Reconfiguration
You can dynamically reconfigure the following PMA controls:
■ Pre-emphasis settings
■ Equalization settings
■ DC gain settings
■ Voltage output differential (V_OD) settings
For more information, refer to “PMA Controls Reconfiguration” on page 2–52.
Transceiver Channel Reconfiguration Modes
Each transceiver block has four regular transceiver channels and two CMU channels.
The regular transceiver channels have both PMA and PCS blocks. The CMU channels
are CMU PLLs configured in Basic (PMA Direct) functional mode as PMA-only
channels. Therefore, the CMU channels have only PMA blocks.
© June 2009 Altera Corporation
HardCopy IV Device Handbook, Volume 3