Quartus® Prime Pro Edition User Guide: Design Constraints

ID 683143
Date 4/01/2024
Document Table of Contents

3.5. Verifying I/O Timing

You must verify board-level signal integrity and I/O timing when assigning I/O pins. High-speed interface operation requires a quality signal and low propagation delay at the far end of the board route. Click Tools > Timing Analyzer to confirm timing after making I/O pin assignments.

For example, if you change the slew rates or drive strengths of some I/O pins with ECOs, you can verify timing without recompiling the design. You must understand I/O timing and what factors affect I/O timing paths in your design. The accuracy of the output load specification of the output and bidirectional pins affects the I/O timing results.

The Quartus® Prime software supports three different methods of I/O timing analysis:

Table 36.  I/O Timing Analysis Methods

I/O Timing Analysis


Advanced I/O timing analysis

Analyze I/O timing with your board trace model to report accurate, “board-aware” simulation models. Configures a complete board trace model for each I/O standard or pin. Timing Analyzer applies simulation results of the I/O buffer, package, and board trace model to generate accurate I/O delays and system level signal information. Use this information to improve timing and signal integrity.

I/O timing analysis

Analyze I/O timing with default or specified capacitive load without signal integrity analysis. Timing Analyzer reports tCO to an I/O pin using a default or user-specified value for a capacitive load.

Full board routing simulation

Use Intel-provided or Quartus® Prime software-generated IBIS or HSPICE I/O models for simulation in Mentor Graphics* HyperLynx* and Synopsys* HSPICE.

For more information about advanced I/O timing support, refer to the appropriate device handbook for your target device. For more information about board-level signal integrity and tips on how to improve signal integrity in your high-speed designs, refer to the Signal Integrity and Power Integrity – Support Center website.

For information about creating IBIS and HSPICE models with the Quartus® Prime software and integrating those models into HyperLynx* and HSPICE simulations, refer to the Signal Integrity Analysis with Third Party Tools chapter.