Xilinx Virtex UltraScale+ FPGAs User Manual page 24

The GTM transceiver TX and RX use a state machine to control the initialization process. They
are partitioned into a few reset regions. The partition allows the reset state machine to control
the reset process in a sequence that the PMA can be reset first and the PCS can be reset after
the assertion of the TXUSERRDY or RXUSERRDY. It also allows the PMA, the PCS, and
functional blocks inside them to be reset individually when needed during normal operation.
The GTM transceiver offers two types of reset: initialization and component.
• Initialization Reset: This reset is used for complete GTM transceiver initialization. It must be
used after device power-up and configuration. During normal operation, when necessary,
GTTXRESET and GTRXRESET can also be used to reinitialize the GTM transceiver TX and RX.
GTTXRESET is the initialization reset port for the GTM transceiver TX. GTRXRESET is the
initialization reset port for the GTM transceiver RX. During initialization reset,
TXRESETMODE and RXRESETMODE should be set to sequential mode. All TX PMA, TX PCS,
RX PMA, and RX PCS component resets should be enabled by setting all required component
bits of TXPMARESETMASK, TXPCSRESETMASK, RXPMARESETMASK, and
RXPCSRESETMASK to High.
• Component Reset: This reset is used for special cases and specific subsection resets while the
GTM transceiver is in normal operation. The component that is required to be reset is selected
by setting the associated bit within TXPMARESETMASK, TXPCSRESETMASK,
RXPMARESETMASK, or RXPCSRESETMASK to High. A TX component reset is triggered by
toggling the GTTXRESET port. An RX component reset is triggered by toggling the
GTRXRESET port. Separate component reset ports are available. For the TX, these are
TXCKALRESET, TXFECRESET, TXPCSRESET, and TXPMARESET. For the RX, these are
RXADAPTRESET, RXADCCLKGENRESET, RXBUFRESET, RXCDRFRRESET, RXCDRPHRESET,
RXDFERESET, RXDSPRESET, RXEYESCANRESET, RXFECRESET, RXPCSRESET,
RXPMARESET, and RXPRBSCSCNTRST.
UG581 (v1.0) January 4, 2019
Virtex UltraScale+ GTM Transceivers
GTM Transceiver Initialization Overview
Figure 11:
After Configuration
LCPLL Reset
TX Initialization by
GTTXRESET
TXRESETDONE
Chapter 2: Shared Features
RX Initialization by
GTRXRESET
RXRESETDONE
X20903-052818
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