Altera Cyclone IV - Page 413

Chapter 3: Cyclone IV Dynamic Reconfiguration 3–15
Dynamic Reconfiguration Modes
November 2011 Altera Corporation Cyclone IV Device Handbook,
Volume 2
Figure 3–4 shows the write transaction waveform for Method 1.
Read Transaction
For example, to read the existing V
OD
values from the transmit V
OD
control registers of
the transmitter portion of a specific channel controlled by the ALTGX_RECONFIG
instance, perform the following steps:
1. Set the
logical_channel_address input port to the logical channel address of the
transceiver channel whose PMA controls you want to read (for example,
tx_vodctrl_out ).
2. Set the
rx_tx_duplex_sel port to 2'b10 so that only the transmit PMA controls are
read from the transceiver channel.
3. Ensure that the
busy signal is low before you start a read transaction.
4. Assert the read signal for one
reconfig_clk clock cycle. This initiates the read
transaction.
The
busy output status signal is asserted high to indicate that the dynamic
reconfiguration controller is busy reading the PMA control values. When the read
transaction has completed, the
busy signal goes low. The data_valid signal is asserted
to indicate that the data available at the read control signal is valid.
Figure 3–4. Write Transaction Waveform—Use ‘logical_channel_address port’ Option
Notes to Figure 3–4:
(1) In this waveform example, you are writing to only the transmitter portion of the channel.
(2) In this waveform example, the number of channels connected to the dynamic reconfiguration controller is four. Therefore, the
logical_channel_address port is 2 bits wide.
(2) 2'b00 2'b01
busy
(1)
2'b00 2'b10
3'b111 3'b001
reconfig_clk
write_all
rx_tx_duplex_sel [1:0]
logical_channel_address [1:0]
tx_vodctrl [2:0]