Secure Digital Input Output (Sdio) - Espressif Systems ESP Faq

Chapter 4. Software framework

4.4.11 Secure Digital Input Output (SDIO)

What is the maximum speed supported by the SDIO interface?
• The maximum clock speed supported by ESP32 SDIO is 50 MHz, and ESP32 SDIO supports the Quad mode
at the maximum.
• The maximum clock speed supported by ESP32-S3 SDIO is 80 MHz, and ESP32-S3 SDIO supports the Octal
mode at the maximum.
• The practical speed is influenced by the read and write speed of storage media at the same time.
Does the hardware SDIO interface support SD cards?
Please note that the SDIO hardware only supports the device or slave profile, i.e. it cannot act as a host
to control SDIO devices such as SD cards.
What is the maximum capacity for ESP32 SD card?
• In the SD3.01 Specifications, the SDXC card supports a maximum capacity of 2 TB (2048 GB).
• The ESP32 SDMMC Host also complies with the SD3.01 Specifications, which means up to 2 TB areas of it
can be accessed by peripherals. When accessing the card via SPI bus using the SDSPI driver, there are also 2
TB of areas can be accessed in hardware level.
• In software level, the usable area of the card is also affected by the file system.
Is it possible to use ESP32 SD card together with flash & PSRAM?
• Yes, they can be used simultaneously when they apply different pins.
• Note that when ESP32 uses the SDMMC host driver, the SDMMC Slot0 pins in the ESP32-WROOM and
ESP32-WROVER modules conflict with the flash.
Does ESP-WROOM-S2 module support using SDIO as a slave?
Yes, it does.
Since ESP32-S2 has removed the SDIO interface, does it still support external TF card?
You can use the interface of SPI2/SPI3 to connect an external TF card. When doing so, please use the
SPI mode of the TF card.
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