Visible to Intel only — GUID: mwh1417737689362
Ixiasoft
2.3.1. Recommended Initial SDC Constraints
2.3.2. SDC File Precedence
2.3.3. Iterative Constraint Modification
2.3.4. Creating Clocks and Clock Constraints
2.3.5. Creating I/O Constraints
2.3.6. Creating Delay and Skew Constraints
2.3.7. Creating Timing Exceptions
2.3.8. Example Circuit and SDC File
2.3.7.5.1. Default Multicycle Analysis
2.3.7.5.2. End Multicycle Setup = 2 and End Multicycle Hold = 0
2.3.7.5.3. End Multicycle Setup = 2 and End Multicycle Hold = 1
2.3.7.5.4. Same Frequency Clocks with Destination Clock Offset
2.3.7.5.5. Destination Clock Frequency is a Multiple of the Source Clock Frequency
2.3.7.5.6. Destination Clock Frequency is a Multiple of the Source Clock Frequency with an Offset
2.3.7.5.7. Source Clock Frequency is a Multiple of the Destination Clock Frequency
2.3.7.5.8. Source Clock Frequency is a Multiple of the Destination Clock Frequency with an Offset
Visible to Intel only — GUID: mwh1417737689362
Ixiasoft
2.3.4.3.1. Clock Divider Example (-divide_by)
A common form of generated clock is the divide-by-two register clock divider. The following example constraint creates a half-rate clock on the divide-by-two register.
create_clock -period 10 -name clk_sys [get_ports clk_sys] create_generated_clock -name clk_div_2 -divide_by 2 -source \ [get_ports clk_sys] [get_pins reg|q]
To specify the clock pin of the register as the clock source:
create_clock -period 10 -name clk_sys [get_ports clk_sys] create_generated_clock -name clk_div_2 -divide_by 2 -source \ [get_pins reg|clk] [get_pins reg|q]
Figure 47. Clock Divider
Figure 48. Clock Divider Waveform