Altera Cyclone IV Device Handbook page 387

Chapter 2: Cyclone IV Reset Control and Power Down
Transceiver Reset Sequences
Receiver and Transmitter Channel—Receiver CDR in Automatic Lock Mode
This configuration contains both a transmitter and a receiver channel. If you create a
Receiver and Transmitter instance in the ALTGX MegaWizard Plug-In Manager with
the receiver CDR in automatic lock mode, use the reset sequence shown in
Figure 2–8. Sample Reset Sequence of Receiver and Transmitter Channel—Receiver CDR in Automatic Lock Mode
Reset Signals
1
pll_areset
tx_digitalreset
rx_analogreset
rx_digitalreset
Output Status Signals
busy (2)
pll_locked
rx_freqlocked
Notes to Figure 2–8:
(1) For t duration, refer to the
LTD_Auto
(2) The busy signal is asserted and deasserted only during initial power up when offset cancellation occurs. In subsequent reset sequences, the busy
signal is asserted and deasserted only if there is a read or write operation to the ALTGX_RECONFIG megafunction.
As shown in
CDR automatic lock mode:
1. After power up, assert pll_areset for a minimum period of 1 s (the time
between markers 1 and 2).
2. Keep the tx_digitalreset, rx_analogreset, and rx_digitalreset signals
asserted during this time period. After you deassert the pll_areset signal, the
multipurpose PLL starts locking to the transmitter input reference clock.
3. After the multipurpose PLL locks, as indicated by the pll_locked signal going
high (marker 3), deassert tx_digitalreset. For receiver operation, after
deassertion of busy signal, wait for two parallel clock cycles to deassert the
rx_analogreset signal.
4. Wait for the rx_freqlocked signal to go high (marker 7).
5. After the rx_freqlocked signal goes high, wait for at least t
the rx_digitalreset signal (marker 8). At this point, the transmitter and receiver
are ready for data traffic.
September 2014 Altera Corporation
1 µs
2
4
Two parallel clock cycles
5
3
Cyclone IV Device Datasheet chapter.
Figure 2–8, perform the following reset procedure for the receiver in
6
8
7
t (1)
LTD_Auto
2–13
Figure 2–8.
, then deassert
LTD_Auto
Cyclone IV Device Handbook,
Volume 2