AN 940: Incremental Block-Based Compilation Tutorial: for Intel® Agilex™ F-Series FPGA Development Board

ID 691276
Date 12/10/2021
Public

1.3.2. Step 2: Identify Timing-Critical Design Blocks

Follow these steps to identify the timing-critical design blocks in the Intel® Quartus® Prime Timing Analyzer:
  1. To run the report_timing.tcl script that identifies any failing paths in the timing-critical design blocks, type the following command in the Console window. If not already visible, click View > Console in the Timing Analyzer to display the Console. The script runs commands to identify any failing paths.
    source report_timing.tcl

    The tcl script runs the report_timing command, capturing timing for the top 100 paths with the worst slack. The script is also preconfigured to capture timing between specific nodes for some of the design blocks. You analyze timing for these nodes later in this tutorial.

    Figure 5. Failing Path in Timing Analyzer Report Folder
    Table 2.  Timing Analysis Reports that report_timing.tcl Generates
    Timing Analysis Folder Generated For Timing Reports Show
    inst_big u_big_partition1_top Analysis of top 100 paths with worst slack
    inst_i1 u_blinking_led_i1
    inst_i2 u_blinking_led_i2
    inst_i3 u_blinking_led_i3
    inst_i4 u_blinking_led_i4
    inst_i1_path1 u_blinking_led_i1 Analysis of timing between specific nodes
    inst_i2_path1 u_blinking_led_i2
  2. View the reports that generate in the Report pane. The inst_i4 report is in red text, indicating timing-critical design blocks with failing paths.
  3. Click the inst_i4 report. Check the values in the From Node and To Node fields. Analysis indicates that the failing paths in u_blinking_led_i4 are in the 64-bit counter. This counter counts the number of cycles equivalent to 16s, where each cycle is of 1.818 ns.
    Figure 6. Multi Corner Summary for u_blinking_led_i4