EP4CE30F29C7N Datasheet, PDF (417/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

Chapter 3: Cyclone IV Dynamic Reconfiguration
Dynamic Reconfiguration Modes
3–19
Method 3: Writing Different Control Signals for all the Transceiver Channels
at the Same Time
If you disable the Use the same control signal for all the channels option, the PMA
control ports for a write transaction are separate for each channel. If you disable this
option, the width of the PMA control ports are fixed as follows:
PMA Control Ports Used in a Write Transaction
■ tx_vodctrl is 3 bits per channel
■ tx_preemp are 5 bits per channel
■ rx_eqdcgain is 2 bits per channel
■ rx_eqctrl is 4 bits per channel
For example, if you have two channels, the tx_vodctrl is 6 bits wide
(tx_vodctrl [2:0] corresponds to channel 1 and tx_vodctrl [5:3] corresponds to
channel 2).
PMA Control Ports Used in a Read Transaction
The width of the PMA control ports for a read transaction are always separate for each
channel as explained in “Method 2: Writing the Same Control Signals to Control All
the Transceiver Channels” on page 3–16.
Write Transaction
Because the PMA controls of all the channels are written, if you want to reconfigure a
specific channel connected to the ALTGX_RECONFIG instance, set the new value at
the corresponding PMA control port of the channel under consideration and retain
the previously stored values in the other active channels with a read transaction prior
to this write transaction.
For example, if the number of channels controlled by the ALTGX_RECONFIG
instance is two, the tx_vodctrl signal in this case would be 6 bits wide. The
tx_vodctrl[2:0] signal corresponds to channel 1 and the tx_vodctrl[5:3] signal
corresponds to channel 2.
■ To dynamically reconfigure the PMA controls of only channel 2 with a new value,
first perform a read transaction to retrieve the existing PMA control values from
tx_vodctrl_out[5:0]. Use the tx_vodctrl_out[2:0] value for tx_vodctrl[2:0]
to write in channel 1. By doing so, channel 1 is overwritten with the same value.
■ Perform a write transaction. This ensures that the new values are written only to
channel 2 while channel 1 remains unchanged.
November 2011 Altera Corporation
Cyclone IV Device Handbook,
Volume 2