SPRUHZ7K August 2015 – April 2024 AM5706 , AM5708 , AM5716 , AM5718 , AM5718-HIREL
The device allows booting from eMMC embedded memories or SD cards connected to device embedded MMC2 or MMC1 controllers I/Os, respectively. The booting interface is selected by configuration of the SYSBOOT pins.
The device high speed MMC/SD/SDIO host controller handles the physical layer, while the ROM code handles the simplified logical protocol layer (read-only protocol). A limited range of commands is implemented in the ROM code.
The SD card interface supports 1.8-V/3-V digital I/Os. The selection on I/O voltage level is done using the PBIAS circuitry. The PBIAS reference level is sensed by the ROM code and PBIAS cell voltage setup appropriately before any communication with the SD card device. The eMMC interface supports also 1.8-V/3-V digital I/Os but with the difference that there is no PBIAS circuitry to select the I/O voltage level. This voltage depends only on the voltage provided to the eMMC associated power pads.
The device supports three booting modes:
File system mode is only supported when booting from an eMMC user area. It is not supported in the eMMC boot area.