This bootloader does SOC initializations and attempts to boot R5 image by the name "app_{corename}", C7x image by the name "dsp_{corename}", present in the first FAT partition found in the connected SD card.
The image name for different cores can be as follows
CORE | IMAGE NAME |
---|---|
r5fss0-0 | app_r50_0 |
r5fss0-1 | app_r50_1 |
r5fss1-0 | app_r51_0 |
r5fss1-1 | app_r51_1 |
c75ss0-0 | app_dsp0_0 |
c75ss1-0 | app_dsp0_1 |
The file can be copied to the SD card by connecting it to the host PC using a card reader. Make sure that the images are named without any file extension. If the card is new, make sure that it is formatted with FAT32/16.
If a multicore appimage file is found at the location, the SBL reads the file metadata into a buffer, parses it, and identifies the program segments for each core applicable. These program segments are then read from respective offset as per the metadata and loads it to corresponding load address. Each core is then initialized, entry points are set and the core is released from reset.
Since the image is loaded segment wise directly from SD card to load addresses it eliminates the usage of large intermediate scratch buffer to hold the complete image. For more on bootflow/bootloaders, please refer Understanding the bootflow and bootloaders
Parameter | Value |
---|---|
CPU + OS | wkup-r5fss0-0 freertos |
Toolchain | ti-arm-clang |
Boards | am275x-evm |
Example folder | examples/drivers/boot/sbl_sd |
Since this is a bootloader, the example will be run every time you boot an application using this example. It is run from an SD card unlike other examples which are usually loaded with CCS. Nevertheless, you can build this example like you do for the others using makefile or build it via CCS by importing as a project.