EP4CE30F29C7N Datasheet, PDF (392/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

2–18
Chapter 2: Cyclone IV Reset Control and Power Down
Transceiver Reset Sequences
PCIe Initialization/Compliance Phase
After the device is powered up, a PCIe-compliant device goes through the compliance
phase during initialization. The rx_digitalreset signal must be deasserted during
this compliance phase to achieve transitions on the pipephydonestatus signal, as
expected by the link layer. The rx_digitalreset signal is deasserted based on the
assertion of the rx_freqlocked signal.
During the initialization/compliance phase, do not use the rx_freqlocked signal to
trigger a deassertion of the rx_digitalreset signal. Instead, perform the following
reset sequence:
1. After power up, assert pll_areset for a minimum period of 1 s (the time
between markers 1 and 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 input reference
clock.
2. After the multipurpose PLL locks, as indicated by the pll_locked signal going
high (marker 3), deassert tx_digitalreset. For a receiver operation, after
deassertion of busy signal, wait for two parallel clock cycles to deassert the
rx_analogreset signal. After rx_analogreset is deasserted, the receiver CDR
starts locking to the receiver input reference clock.
3. Deassert both the rx_analogreset signal (marker 6) and rx_digitalreset signal
(marker 7) together, as indicated in Figure 2–10. After deasserting
rx_digitalreset, the pipephydonestatus signal transitions from the transceiver
channel to indicate the status to the link layer. Depending on its status,
pipephydonestatus helps with the continuation of the compliance phase. After
successful completion of this phase, the device enters into the normal operation
phase.
PCIe Normal Phase
For the normal PCIe phase:
1. After completion of the Initialization/Compliance phase, during the normal
operation phase at the Gen1 data rate, when the rx_freqlocked signal is
deasserted (marker 9 in Figure 2–10).
2. Wait for the rx_freqlocked signal to go high again. In this phase, the received data
is valid (not electrical idle) and the receiver CDR locks to the incoming data.
Proceed with the reset sequence after assertion of the rx_freqlocked signal.
3. After the rx_freqlocked signal goes high, wait for at least t_{LTD_Manual} before
asserting rx_digitalreset (marker 12 in Figure 2–10) for two parallel receive
clock cycles so that the receiver phase compensation FIFO is initialized. For
bonded PCIe Gen 1 mode (×2 and ×4), wait for all the rx_freqlocked signals to go
high, then wait for t_{LTD_Manual} before asserting rx_digitalreset for 2 parallel clock
cycles.
Cyclone IV Device Handbook,
Volume 2
May 2013 Altera Corporation