Visible to Intel only — Ixiasoft
Visible to Intel only — Ixiasoft
Follow the timing guidelines and examples to ensure that the Timing Analyzer analyzes the I/O timing correctly.
- To perform proper timing analysis for the I/O interface paths, specify the system level constraints of the data pins against the system clock pin in the .sdc file.
- To perform proper timing analysis for the core interface paths, define these clock settings in the .sdc file:
- Clock to the core registers
- Clock to the I/O registers for the simple register and DDIO modes
Single Data Rate Input Register
Command | Command Example | Description |
---|---|---|
create_clock | create_clock -name sdr_in_clk -period "100 MHz" sdr_in_clk | Creates clock setting for the input clock. |
set_input_delay | set_input_delay -clock sdr_in_clk 0.15 sdr_in_data | Instructs the Timing Analyzer to analyze the timing of the input I/O with a 0.15 ns input delay. |
Full-Rate or Half-Rate DDIO Input Register
Command | Command Example | Description |
---|---|---|
create_clock | create_clock -name virtual_clock -period "200 MHz" create_clock -name ddio_in_clk -period "200 MHz" ddio_in_clk |
Create clock setting for the virtual clock and the DDIO clock. |
set_input_delay | set_input_delay -clock virtual_clock 0.25 ddio_in_data set_input_delay -add_delay -clock_fall -clock virtual_clock 0.25 ddio_in_data |
Instruct the Timing Analyzer to analyze the positive clock edge and the negative clock edge of the transfer. Note the -add_delay in the second set_input_delay command. |
set_false_path | set_false_path -fall_from virtual_clock -rise_to ddio_in_clk set_false_path -rise_from virtual_clock -fall_to ddio_in_clk |
Instruct the Timing Analyzer to ignore the positive clock edge to the negative edge triggered register, and the negative clock edge to the positive edge triggered register.
Note: The ck_hr frequency must be half the ck_fr frequency. If the I/O PLL drives the clocks, you can consider using the derive_pll_clocks .sdc command.
|
Single Data Rate Output Register
Command | Command Example | Description |
---|---|---|
create_clock and create_generated_clock | create_clock -name sdr_out_clk -period "100 MHz" sdr_out_clk create_generated_clock -source sdr_out_clk -name sdr_out_outclk sdr_out_outclk |
Generate the source clock and the output clock to transmit. |
set_output_delay | set_output_delay -clock sdr_out_clk 0.45 sdr_out_data | Instructs the Timing Analyzer to analyze the output data to transmit against the output clock to transmit. |