Xilinx Virtex UltraScale+ FPGAs User Manual page 25

All reset ports described in this section initiate the internal reset state machine when driven
High. The internal reset state machines are held in the reset state until these same reset ports are
driven Low. These resets are all asynchronous. The guideline for the pulse width of these
asynchronous resets is one period of the reference clock, unless otherwise noted.
:
Note Do not use reset ports for the purpose of power down. For details on proper power-down usage,
refer to Power Down.
Resetting Multiple Lanes and Quads
Resetting multiple lanes in a Dual or multiple Duals affects the power supply regulation circuit.
Reset Modes
The GTM transceiver TX and RX resets can operate in two different modes: sequential mode and
single mode.
• Sequential mode: The reset state machine starts with an initialization or component reset
input driven High and proceeds through all states after the requested reset states in the reset
state machine, as shown in
transceiver RX until completion. The completion of sequential mode reset flow is signaled
when (TX/RX)RESETDONE transitions from Low to High.
• Single mode: The reset state machine only executes the requested component reset
independently for a predetermined time set by its attribute. It does not process any state after
the requested state, as shown in
GTM transceiver RX. The requested reset can be any component reset to reset the PMA, the
PCS, or functional blocks inside them. The completion of a single mode reset is signaled when
(TX/RX)RESETDONE transitions from Low to High.
The GTM transceiver initialization reset must use sequential mode. All component resets can be
operated in either sequential mode or single mode. The GTM transceiver uses (TX/
RX)RESETMODE to select between sequential reset mode and single reset mode. The following
table provides configuration details that apply to both the GTM transceiver TX and GTM
transceiver RX. Reset modes have no impact on LCPLL reset. During normal operation, the GTM
transceiver TX or GTM transceiver RX can be reset by applications in either sequential mode or
single mode (GTM transceiver RX only), which provides flexibility to reset a portion of the GTM
transceiver. When using either sequential mode or single mode, (TX/RX)RESETMODE must be
set to the desired value of 50 ns before the assertions of any reset.
Table 11: GTM Transceiver Reset Modes Operation
UG581 (v1.0) January 4, 2019
Virtex UltraScale+ GTM Transceivers
Figure 13
Figure 13
Operation Mode
Sequential Mode
Single Mode
for the GTM transceiver TX or
for the GTM transceiver TX or
(TX/RX)RESETMODE
Send Feedback
Chapter 2: Shared Features
Figure 18 for the GTM
Figure 18 for the
2'b00
2'b11
www.xilinx.com
25