Altera Cyclone IV - Page 388

2–14 Chapter 2: Cyclone IV Reset Control and Power Down
Transceiver Reset Sequences
Cyclone IV Device Handbook, September 2014 Altera Corporation
Volume 2
Receiver and Transmitter Channel—Receiver CDR in Manual Lock Mode
This configuration contains both a transmitter and receiver channel. If you create a
Receiver and Transmitter instance in the ALTGX MegaWizard Plug-In Manager with
the receiver CDR in manual lock mode, use the reset sequence shown in Figure 2–9.
As shown in Figure 2–9, perform the following reset procedure for the receiver in
manual 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 , rx_digitalreset , and
rx_locktorefclk signals asserted and the rx_locktodata signal deasserted 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 (marker 4). For receiver operation,
after deassertion of busy signal (marker 5), wait for two parallel clock cycles to
deassert the
rx_analogreset signal (marker 6). After rx_analogreset deassert,
rx_pll_locked will assert.
Figure 2–9. Sample Reset Sequence of Receiver and Transmitter Channel—Receiver CDR in Manual Lock Mode
Notes to Figure 2–9:
(1) For t
LTR_LTD_Manual
duration, refer to the Cyclone IV Device Datasheet chapter.
(2) For t
LTD_Manual
duration, refer to the Cyclone IV Device Datasheet chapter.
(3) 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.
Reset Signals
Output Status Signals
12
3
4
6
7
8
CDR Control Signals
7
busy (3)
5
Two parallel clock cycles
1 µs
pll_areset
tx_digitalreset
rx_analogreset
rx_digitalreset
rx_locktorefclk
rx_locktodata
pll_locked
t
LTD_Manual
(2)
t
LTR_LTD_Manual
(1)