AN 886: Intel Agilex® 7 Device Design Guidelines

ID 683634
Date 10/09/2023
Document Table of Contents SD/MMC and eMMC Card Interface Design Guidelines

The Secure Digital/Multimedia Card (SD/MMC) controller, based on the Synopsys* DesignWare* attached to the hard processor system (HPS) is used for mass storage. This module supports:
  • SD version 3.01, in addition to 3.0
  • Embedded MMC (eMMC) version 4.51 and 5.0, in addition to 4.54

GUIDELINE: Ensure that voltage translation transceivers are properly implemented if using 1.8V SD card operation.

HPS I/O use a fixed voltage level of 1.8 V. Many SD cards have an option to signal at 1.8 V or 3.3 V, although the initial power-up voltage requirement is 3.3 V. In cases when you want to use a 3.3 V SD card, voltage switching is required. To have the correct voltage level to power the card, voltage translation transceivers are required.

Follow the guidelines in the Voltage Switching section of the SD/MMC Controller chapter in the Intel Agilex® 7 Hard Processor System Technical Reference Manual

Table 24.  Level Shifter Requirements
HPS I/O Bank Voltage SD Card Voltage Level Shifter Needed
1.8 V 3.0 V Yes
1.8 V 1.8 V No
4 The HS400 mode is not supported.