Power on
Run the ROM boot
loader in ROM
Copy the user
boot loader in
MMC/SD
to IRAM
Jump to user boot
loader entry point
in IRAM
Copu user MAIN
program in
MMC/SD
to DDR
Run MAIN program
in DDR
ROM boot loader
User boot loader
ARM ROM Boot Modes
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The MMC/SD RBL will use the hardware CRC error detection capability to determine if a read error occurs
when reading the UBL including the UBL descriptor. If a read error occurs, the UBL copy will immediately
halt for that instance of magic number but the RBL will continue to search the block following that block in
which the magic number was found for another instance of a magic number. When a magic number is
found, the process is repeated. Using this retry process, the magic number and UBL can be duplicated up
to 24 times, giving significant redundancy and error resilience to MMC/SD read errors.
Figure 11-9. MMC/SD Boot Mode Overview
Boot Modes
160
SPRUFX7 – July 2008