HC4GX15 Datasheet, PDF (516/668 Pages) Altera Corporation – HardCopy IV Device Handbook

2–58
Chapter 2: HardCopy IV GX Dynamic Reconfiguration
PMA Controls Reconfiguration
Write Transaction
The value you set at the selected PMA control ports gets written to all the transceiver
channels connected to the ALTGX_RECONFIG instance.
Consider that you have enabled tx_vodctrl in the ALTGX_RECONFIG
MegaWizard Plug-In Manager to reconfigure the V_OD of the transceiver channels.
The following are the steps involved in the write transaction to reconfigure the V_OD, as
shown in Figure 2–24:
1. Before you initiate a write transaction, set the selected PMA control ports to the
desired settings (for example, tx_vodctrl = 3'b000).
2. Set the rx_tx_duplex_sel[1:0] port to 2'b10 so that only the transmit PMA
controls are written to the transceiver channel.
3. Ensure that the busy signal is low before you start a write transaction.
4. Assert the write_all signal for one reconfig_clk clock cycle. This initiates
the write transaction.
5. The busy output status signal is asserted high to indicate that the dynamic
reconfiguration controller is busy writing the PMA control values. Once the write
transaction has completed, the busy signal goes low.
Figure 2–24. Method 2: Write Transaction Waveform—Use the Same Control Signal for All Channels Option Enabled
reconfig_clk
write_all
rx_tx_duplex_sel [1:0] (1) ^2’b00
busy
tx_vodctrl [2:0]
3’b000
2’b10
3’b111
Note to Figure 2–24:
(1) Consider that you want to write to only the transmitter portion of the channel.
HardCopy IV Device Handbook, Volume 3
© June 2009 Altera Corporation