
Table 44: TX Programmable Divider Attribute (cont'd)
Attribute
Type
Description
TX_PROGDIV_PDBV_DIV5
[2]
This attribute is used during the TX programmable divider
ratio selection.
•
The attribute must be set to
1’b0
when the desired
divider value is either 16.5, 33, 66, or 132.
•
For all other divider values, this should be set to
1’b1
.
Ports and Attributes
The following table defines the ports required for TX fabric clock output control.
Table 45: TX Fabric Clock Output Control Ports
Port
Dir
Clock
Domain
Description
CH[0/1]_TXOUTCLKSEL[2:0]
In
Async
This port must be set to
3'b000
.
CH[0/1]_TXOUTCLK
Out
Clock
Reserved.
CH[0/1]_TXPROGDIVCLK
Out
Clock
TXPROGDIVCLK is the parallel output clock from the
TX programmable divider. This clock is the
recommended output to the interconnect logic
through BUFG_GT.
TX Configurable Driver
The GTM transceiver TX driver is a high-speed voltage-mode differential output buffer. To
maximize signal integrity, it includes these features:
• Differential voltage control
• Two pre-cursor, and one post-cursor transmit pre-emphasis
• Two modulation schemes: NRZ and PAM4
• Calibrated termination resistors
Chapter 3: Transmitter
UG581 (v1.0) January 4, 2019
Virtex Ult GTM Transceivers
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