Intel® Quartus® Prime Pro Edition User Guide: Getting Started

ID 683463
Date 12/12/2022

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4.8. Plan for Interface I/O Pins

In many design environments, FPGA designers want to plan the top-level FPGA I/O pins early to help board designers begin the PCB design and layout. The I/O capabilities and board layout guidelines of the FPGA device influence pin locations and other types of assignments. If the board design team specifies an FPGA pin-out, the pin locations must be verified in the FPGA placement and routing software to avoid board design changes.

You can create a preliminary pin-out for an Intel FPGA with the Intel® Quartus® Prime Pin Planner before you develop the source code, based on standard I/O interfaces (such as memory and bus interfaces) and any other I/O requirements for your system.

Figure 46. Pin Planner

The Intel® Quartus® Prime I/O Assignment Analysis checks that the pin locations and assignments are supported in the target FPGA architecture. You can then use I/O Assignment Analysis to validate I/O-related assignments that you create or modify throughout the design process. When you compile your design in the Intel® Quartus® Prime software, I/O Assignment Analysis runs automatically in the Fitter to validate that the assignments meet all the device requirements and generates error messages.

Early in the design process, before creating the source code, the system architect has information about the standard I/O interfaces (such as memory and bus interfaces), the IP cores in your design, and any other I/O-related assignments defined by system requirements. You can use this information with the Early Pin Planning feature in the Pin Planner to specify details about the design I/O interfaces. You can then create a top-level design file that includes all I/O information.

The Pin Planner interfaces with the IP core parameter editor, which allows you to create or import custom IP cores that use I/O interfaces. You can configure how to connect the functions and cores to each other by specifying matching node names for selected ports. You can create other I/O-related assignments for these interfaces or other design I/O pins in the Pin Planner, as described in this section. The Pin Planner creates virtual pin assignments for internal nodes, so internal nodes are not assigned to device pins during compilation.

You can use the I/O analysis results to change pin assignments or IP parameters even before you create your design, and repeat the checking process until the I/O interface meets your design requirements and passes the pin checks in the Intel® Quartus® Prime software. When you complete initial pin planning, you can create a revision based on the Intel® Quartus® Prime-generated netlist. You can then use the generated netlist to develop the top-level design file for your design, or disregard the generated netlist and use the generated Intel® Quartus® Prime Settings File (.qsf) with your design.

During this early pin planning, after you have generated a top-level design file, or when you have developed your design source code, you can assign pin locations and assignments with the Pin Planner.

With the Pin Planner, you can identify I/O banks, voltage reference (VREF) groups, and differential pin pairings to help you through the I/O planning process. If you selected a migration device, the Pin Migration View highlights the pins that have changed functions in the migration device when compared to the currently selected device. Selecting the pins in the Device Migration view cross-probes to the rest of the Pin Planner, so that you can use device migration information when planning your pin assignments. You can also configure board trace models of selected pins for use in “board-aware” signal integrity reports generated with the Enable Advanced I/O Timing option . This option ensures that you get accurate I/O timing analysis. You can use a Microsoft Excel spreadsheet to start the I/O planning process if you normally use a spreadsheet in your design flow, and you can export a Comma-Separated Value File (.csv) containing your I/O assignments for spreadsheet use when you assign all pins.

When you complete your pin planning, you can pass pin location information to PCB designers. The Pin Planner is tightly integrated with certain PCB design EDA tools, and can read pin location changes from these tools to check suggested changes. Your pin assignments must match between the Intel® Quartus® Prime software and your schematic and board layout tools to ensure the FPGA works correctly on the board, especially if you must make changes to the pin-out. The system architect uses the Intel® Quartus® Prime software to pass pin information to team members designing individual logic blocks, allowing them to achieve better timing closure when they compile their design.

Start FPGA planning before you complete the HDL for your design to improve the confidence in early board layouts, reduce the chance of error, and improve the overall time to market of the design. When you complete your design, use the Fitter reports for the final sign-off of pin assignments. After compilation, the Intel® Quartus® Prime software generates the Pin-Out File (.pin), and you can use this file to verify that each pin is correctly connected in board schematics.