HC4GX15 Datasheet, PDF (505/668 Pages) Altera Corporation – HardCopy IV Device Handbook

Chapter 2: HardCopy IV GX Dynamic Reconfiguration
2–47
Offset Cancellation Control for Receiver Channels
1 The gxb_powerdown signal must not be asserted during the offset cancellation
sequence.
1 To understand the impact on system start-up when you control all the transceiver
channels using a single dynamic reconfiguration controller, refer to “PMA Controls
Reconfiguration Duration” on page 2–143.
In this example, the design has ALTGX instances with channels of both Transmitter
only and Receiver only configurations. You must include the Transmitter only
channels while setting the What is the starting channel number? option in the
ALTGX instance and setting the What is the number of channels controlled by the
reconfig controller? option in the ALTGX_RECONFIG instance for receiver offset
cancellation.
■ After the device powers up, the busy signal remains low for the first
reconfig_clk clock cycle.
■ The busy signal then gets asserted for the second reconfig_clk clock cycle,
when the dynamic reconfiguration controller initiates the offset cancellation
process.
■ The de-assertion of the busy signal indicates the successful completion of the
offset cancellation process.
Figure 2–16 shows the dynamic reconfiguration signals transition during offset
cancellation on receiver channels.
Figure 2–16. Dynamic Reconfiguration Signals Transition during Offset Cancellation on Receiver Channels
reconfig_clk
busy
(1)
Note to Figure 2–16:
(1) After device power up, the busy signal remains low for the first reconfig_clk cycle.
1 Due to the offset cancellation process, the transceiver reset sequence has changed. For
more information, refer to the Reset Control and Power Down chapter in volume 2 of the
Stratix IV Device Handbook.
© June 2009 Altera Corporation
HardCopy IV Device Handbook, Volume 3