MAX® 10 General Purpose I/O User Guide

ID 683751
Date 3/17/2025
Public
Document Table of Contents

3.8. Guidelines: External Memory Interface I/O Restrictions

These I/O rules are applicable if you use external memory interfaces in your design.

Two GPIOs Adjacent to DQ Pin Is Disabled

This limitation is applicable to MAX® 10 10M16, 10M25, 10M40, and 10M50 devices, and only if you use DDR3 and LPDDR2 SDRAM memory standards.

For more information about the unavailable I/O pins in the affected device packages, refer to the MAX® 10 External Memory Interface Design Considerations chapter of the MAX® 10 External Memory Interface User Guide.

Table 24.  DDR3 and LPDDR2 Memory Interface Widths and Device Packages Where Two GPIOs Adjacent to DQ Pins Are DisabledThis table lists the combination of MAX® 10 10M16, 10M25, 10M40, and 10M50 device packages, and DDR3 and LPDDR2 memory interface widths where you cannot use two GPIO pins that are adjacent to the DQ pins.
Device Package Memory Interface Width (DDR3 and LPPDR2 only)
F256 x8, x16
U324 x8, x16
F484 x8, x16, x24
F672 x8, x16, x24
B610 x8, x16, x24

Total I/O Utilization in Bank Must Be 75% or Less in Some Devices

If you use DDR3 or LPDDR2 SDRAM memory interface standards, the two I/O pins adjacent to the DQ pins are not available for use. You can generally use 75% of the total number of I/O pins available in I/O banks 5 and 6 for normal I/O operation. This restriction differs from device to device. In some device packages you can use all 100% of the I/Os. The Quartus® Prime software outputs an error message if the restriction rule affects the I/O usage per bank of the device.

If you use DDR2 memory interface standards, you can assign 75% of the available I/O pins in I/O banks 5 and 6 for normal I/O operation. You can assign the remaining 25% of the I/O pins as input pins only.

For more information about DDR2, DDR3, and LPPDR2 board design requirement, refer to the related information.