SDIO Driver

The SDIO (Secure Digital Input/Output) is a universal I/O interface protocol extended from the SD memory card standard, widely used in fields including IoT, consumer electronics, and industrial control.

The JH7110 SoC is equipped with two SDIO interfaces. By default, SDIO0 is used for eMMC, while SDIO1 is reserved for SD cards or peripherals such as Wi-Fi. On the RT-Thread side, SDIO1 is the interface in use.

The RTOS includes an SDIO driver, with its files located at the following paths:

rtthread/bsp/starfive/libraries/driver/drv_sdmmc.c
rtthread/bsp/starfive/libraries/hal/sdmmc

The following table describes the common operations on SD cards:

Table 1. SD Card Operations
Operation	Command	Description
Mount SD card to root directory	`# mount SDIO1 / elm`	Mounts the SD card to the root directory.
Unmount SD card	`# umount /`	Unmounts the SD card from the root directory.
Copy file to SD card	`# cd` `# echo “12345” test.txt/`	Navigates to the root directory, and then creates a file `test.txt` with content "12345" (saves to the mounted SD card).
Delete file from SD card	`# cd /# rm test.txt`	Navigates to the root directory, and then deletes the `test.txt` file from the SD card.
Create sub-directory	`# cd /` `# mkdir mnt`	Navigates to the root directory, then creates a subdirectory `mnt`on the SD card. Successful execution confirms normal device mount/unmount and read/write functions.
Format SD card as FATFS	`# mkfs -t elm SDIO1`	Formats the SD card to the FATFS file system. Execution duration varies based on the SD card’s capacity and speed class.