SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Boot operation mode lets the eMMC/SD/SDIOi host controller read boot data from the connected slave (MMC device) by keeping the CMD line low after power on (or sending CMD0 with a specific argument) before issuing CMD1. The data can be read from the boot area or user area, depending on the register setting.
Power-on boot defines a way for the boot code to be accessed by the eMMC/SD/SDIOi host controller without an upper-level software driver, thus speeding the time it takes for a controller to access the boot code.
The two possible ways to issue a boot command (issuing a CMD0 or driving the CMD line to 0 during the whole boot phase) are described in the following sections.