Step 1: Understanding the Design - 2022.1 English

Vivado Design Suite Tutorial: Design Analysis and Closure Techniques (UG938)

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2022.1 English

This lab uses an architected design to demonstrate some of the features of RQS. Suggestions are triggered by the design of the RTL and the placement of blocks using floorplanning. The design contains the following modules:

Clocking Module
The main clocking circuit for the design resides in clocking_module.vhd. For simplicity, RST is tied to GND. LOCKED is registered and tied to an output port. The structure of this block is shown in the following figure.

Reg CLKA to CLKB Module
This module contains a synchronous CDC for a large bus. It registers input data using CLKA and then passes it to a register on the CLKB domain to be passed to the output. Registering large buses on different related clock domains can impact hold slack (WHS/THS) and setup slack (WNS/TNS).
Bit Expander and Bit Reducer Modules
These modules enable the expansion and contraction of internal data widths so that the design does not run out of I/Os. The modules take an arbitrary data width and expand or contract it to or from a desired size. The contraction logic creates many logic levels.

The following steps cover opening the project and examining the placement of the floor-planned modules.

  1. In the Vivado Design Suite, go to File > Project > Open and select the project located in <extract_Dir>/Lab2/project_2.

  2. In the Flow Navigator, click Run Synthesis and wait for synthesis to complete.
  3. In the Flow Navigator, click Open Synthesized Design.
  4. In the Netlist view, look at the hierarchy.

  5. In Device view, look at the pblock. This has been added to control placement of the reg_clka_to_clkb modules and force a poor clock skew.