Podcast
Questions and Answers
What is the purpose of the set_false_path command in timing exceptions?
What is the purpose of the set_false_path command in timing exceptions?
- To specify the design's power requirements
- To ignore certain paths during analysis (correct)
- To increase the clock frequency
- To analyze all paths in the design
Which command is used to indicate that a path may take more than one cycle?
Which command is used to indicate that a path may take more than one cycle?
- set_case_analysis
- set_multicycle_path (correct)
- set_false_path
- set_timing_analysis
What would be the effect of executing the command set_case_analysis 1 [get_ports SLEEP_MODE]?
What would be the effect of executing the command set_case_analysis 1 [get_ports SLEEP_MODE]?
- Disable the SLEEP_MODE functionality
- Assign a constant value to the SLEEP_MODE pin (correct)
- Enable all pins for dynamic analysis
- Delay the timing analysis
In the context of timing exceptions, what does the option -hold signify when using set_multicycle_path?
In the context of timing exceptions, what does the option -hold signify when using set_multicycle_path?
Which of the following is NOT a purpose of the commands discussed in the content?
Which of the following is NOT a purpose of the commands discussed in the content?
What is the setup slack for the timing end-point FF1/D?
What is the setup slack for the timing end-point FF1/D?
What is the calculated hold slack at the timing end-point FF1/D?
What is the calculated hold slack at the timing end-point FF1/D?
What clock period was used in the calculations in this content?
What clock period was used in the calculations in this content?
What is the required time at the timing end-point port Z?
What is the required time at the timing end-point port Z?
What is the arrival time at the timing end-point port Z?
What is the arrival time at the timing end-point port Z?
What does the command 'set_clock_latency' specify?
What does the command 'set_clock_latency' specify?
Which command is used to create a clock signal?
Which command is used to create a clock signal?
What is modeled by clock uncertainty in a circuit design?
What is modeled by clock uncertainty in a circuit design?
What does the command 'set_clock_uncertainty 15 -hold' specify about a clock signal?
What does the command 'set_clock_uncertainty 15 -hold' specify about a clock signal?
What is the purpose of 'set_clock_transition' in clock signal attributes?
What is the purpose of 'set_clock_transition' in clock signal attributes?
Which aspect does the environment of design add constraints to?
Which aspect does the environment of design add constraints to?
What must be checked at the output port concerning setup/hold requirements?
What must be checked at the output port concerning setup/hold requirements?
What does the term 'jitter' refer to in the context of clock uncertainty?
What does the term 'jitter' refer to in the context of clock uncertainty?
What is the primary purpose of Shannon expansion in digital circuit design?
What is the primary purpose of Shannon expansion in digital circuit design?
In the context of timing-driven optimization, what does 'retiming' involve?
In the context of timing-driven optimization, what does 'retiming' involve?
Which of the following best describes fanout optimization?
Which of the following best describes fanout optimization?
Given the setup time of 45 ps and the setup slack must be computed, which timing factor contributes to setup time analysis?
Given the setup time of 45 ps and the setup slack must be computed, which timing factor contributes to setup time analysis?
What should be the approach to improve the worst-case delay in a timing-driven optimization process?
What should be the approach to improve the worst-case delay in a timing-driven optimization process?
What is represented by the terms 'setup time' and 'hold time' in synchronous circuits?
What is represented by the terms 'setup time' and 'hold time' in synchronous circuits?
In designing a circuit with the constraints set in the SDC file, what does 'set_output_delay' define?
In designing a circuit with the constraints set in the SDC file, what does 'set_output_delay' define?
If the arrival time for signal Z is 145 ps and for signal C is 130 ps, what can be inferred about the circuits' performance?
If the arrival time for signal Z is 145 ps and for signal C is 130 ps, what can be inferred about the circuits' performance?
What are the two approaches to technology mapping described?
What are the two approaches to technology mapping described?
What happens to the delay when a smaller cell is replaced with a larger cell in timing-driven optimization?
What happens to the delay when a smaller cell is replaced with a larger cell in timing-driven optimization?
What is the effect of replacing a cell C1 with a larger equivalent cell C2 during resizing?
What is the effect of replacing a cell C1 with a larger equivalent cell C2 during resizing?
What is the primary goal of timing-driven optimization when it comes to rewiring?
What is the primary goal of timing-driven optimization when it comes to rewiring?
In the context of resizing, what assertion is true regarding cell functionalities?
In the context of resizing, what assertion is true regarding cell functionalities?
What is a consequence of moving a timing-critical signal closer to the sink?
What is a consequence of moving a timing-critical signal closer to the sink?
Which of the following can be a result of increasing the size of a cell during timing-driven optimization?
Which of the following can be a result of increasing the size of a cell during timing-driven optimization?
What are the libraries structured to contain in the context of resizing?
What are the libraries structured to contain in the context of resizing?
Study Notes
Synchronous Circuit Analysis - Setup & Hold Slack
- Synchronous Circuit: The circuit uses flip-flops (FF1 and FF2) synchronized by a clock signal.
- Timing Parameters:
- Setup time: 45ps for both FF1 and FF2
- Hold time: 10ps for both FF1 and FF2
- CLK-to-Q delay: 20ps for both FF1 and FF2
- Inverter delay: 50ps for each inverter (G1, G2, G3)
- SDC Constraints:
- Clock Period: 1000ps (defined by
create_clock -name CLK -period 1000) - Input Delay: 150ps at input port A (defined by
set_input_delay -clock [get_clocks CLK] 150 [get_ports A]) - Output Delay: 125ps at output port Z (defined by
set_output_delay -clock [get_clocks CLK] 125 [get_ports Z])
- Clock Period: 1000ps (defined by
Setup Slack at FF1/D
- Arrival time at FF1/D: 150ps (input delay) + 50ps (inverter G1 delay) = 200ps
- Required time at FF1/D: 1000ps (clock period) - 45ps (setup time) = 955ps
- Setup slack at FF1/D: 955ps (required time) - 200ps (arrival time) = 755ps
Hold Slack at FF1/D
- Arrival time at FF1/D: 200ps (as calculated previously)
- Required time at FF1/D: 10ps (hold time)
- Hold slack at FF1/D: 200ps (arrival time) - 10ps (required time) = 190ps
Setup Slack at Output Port Z
- Arrival time at Z: 20ps (CLK-to-Q delay) + 50ps (inverter G3 delay) = 70ps
- Required time at Z: 1000ps (clock period) - 125ps (output delay) = 875ps
- Setup slack at Z: 875ps (required time) - 70ps (arrival time) = 805ps
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Description
This quiz covers the analysis of synchronous circuits, focusing on setup and hold slack calculations. It includes critical timing parameters such as setup time, hold time, and inverter delays while applying SDC constraints. Test your understanding of these concepts through practical calculation examples.
