Xilinx Virtex UltraScale+ FPGAs

3. TXUSRCLK can be ed to 1’b0 if GEN_TXUSRCLK = 1’b1.
TXPROGDIVCLK Driving GTM Transceiver TX in 128-Bit, 160-Bit, or
256-Bit Mode
In the following gure, TXPROGDIVCLK is used to drive TXUSRCLK and TXUSRCLK2 in 128-bit,
160-bit, or 256-bit mode in a single-lane conguraon. In all cases, the frequency of
TXUSRCLK2 is equal to half of the TXUSRCLK frequency.
Figure 28: Single Lane—TXPROGDIVCLK Drives TXUSRCLK and TXUSRCLK2 (128-Bit,
160-Bit, or 256-Bit Mode)
Design in UltraScale
Architecture
÷1
UltraScale
Devices GTM
Transceiver
TXPROGDIVCLK
BUFG_GT
1
TXUSRCLK2
2
TXUSRCLK
2
TXDATA (TX data width = 128/160/256 bits)
÷2
BUFG_GT
1
X20913-111918
Notes relevant to the gure:
1. For details about placement constraints and restricons on clocking resources (such as
BUFG_GT and BUFG_GT_SYNC), refer to the UltraScale Architecture Clocking Resources User
Guide (UG572).
2. F
TXUSRCLK2
= F
TXUSRCLK
/2.
Similarly, the following gure shows the same sengs in a mulple-lane conguraon. In a mul-
lane conguraon, the middle-most GTM transceiver should be selected to be the source of
TXPROGDIVCLK. For example, in a mul-lane conguraon of six GTM transceivers consisng
of three conguous Duals, one of the middle GTM transceivers in the middle Dual should be
selected as the source of TXPROGDIVCLK.
Chapter 3: Transmitter
UG581 (v1.0) January 4, 2019 www.xilinx.com
Virtex UltraScale+ GTM Transceivers 61
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