3. Deassert
tx_digitalreset
after a minimum duration of t
tx_digitalreset
, and after all the gating conditions
are removed:
•
pll_powerdown
is deasserted
•
pll_locked
is deasserted
Figure 3-6: Reset Sequence Timing Diagram for Transmitter using the User-Coded Reset Controller
during Device Operation
pll_locked
tx_digitalreset
tx_analogreset
pll_powerdown
t
pll_powerdown
min 1 μs
t
tx_digitalreset
min 20ns
1
2
3
1
1
t
pll_lock
max 10 μs
tx_cal_busy
mgmt_rst_reset
1
Resetting the Receiver with the User-Coded Reset Controller during Device Power-Up
Configuration
Follow this reset sequence to ensure a reliable receiver initialization after the initial power-up.
The numbers in the following figure correspond to the following numbered list, which guides you through
the receiver reset sequence during device power-up.
1. Assert
mgmt_rst_reset
at power-up to start the calibration IPs. Hold
mgmt_rst_reset
active
for a minimum of two
mgmt_clk_clock
cycles. Hold
rx_analogreset
and
rx_digitalreset
active at power-up to hold the receiver in reset. You can deassert them after all the gating conditions are
removed.
2. After the receiver calibration completes, the
rx_cal_busy
status is de-asserted.
3. Deassert
rx_analogreset
after a minimum duration of t
rx_analogreset
after
rx_cal_busy
is deasserted.
4.
rx_is_lockedtodata
is a status signal from the receiver CDR indicating that the CDR is in the lock
to data (LTD) mode. Ensure
rx_is_lockedtodata
is asserted and stays asserted for a minimum
duration of t
LTD
before deasserting
rx_digitalreset
. If
rx_is_lockedtodata
is asserted and
toggles, you must wait another additional t
LTD
duration before deasserting
rx_digitalreset
.
5. Deassert
rx_digitalreset
after a minimum duration of t
LTD
after
rx_is_lockedtodata
stays
asserted. Ensure
rx_analogreset
and
rx_cal_busy
are deasserted before deasserting
rx_digitalreset
.
The receiver is now out of reset and ready for operation.
rx_is_lockedtodata
might toggle when there is no data at the receiver
input.
Note:
Altera Corporation
Transceiver Reset Control in Cyclone V Devices
3-9
Resetting the Receiver with the User-Coded Reset Controller during Device Power-Up Configuration
CV-53003
2013.05.06