AM243x MCU+ SDK  09.00.00
SBL DFU Uniflash


This is a flash-writer application which works in conjunction with the python script mentioned in Flashing Tools. Although it is not strictly not a bootloader, it uses bootloader APIs to do basic SOC initialization required to be able to flash binaries to the OSPI flash. Like other SBLs, this is also booted by the ROM bootloader. It is analogous to SBL UART Flash Writer

  • DFU which stands for (Device Firmware Upgrade) is a standard device class of USB USB. This application uses DFU to flash the SBLs and application images to ospi/qspi flash.
    • It uses DFU class from TinyUSB stack please refer to USB for more information.

Once the example starts running it attempts to receive files via USB DFU and process them in a loop. Once it receives a file (this is sent by the script), it finds out what to do with the received file from the file header. It can be three things:

  • Flash the received file at the given offset
  • Verify if the data in the received file is present at the given offset
  • Erase the flash at the given offset for the given size

The meta-data required for doing these operations (offset, file size, erase size etc.) will be extracted from the same header.

This example is more or less like a flashing server, and will never terminate until EVM is powered down or the core is reset.

The DFU uniflash differes from SBL UART Flash Writer in response message stage.
  • SBL UART uniflash send the response header back via UART which contains the status information of the requested flash cmd mentioned in the file header.
  • As USB DFU is host driven protocol the response stage differs from the UART uniflash. dfu-util will take care of necessary error handling.
  • Refer to DFU_1.1.pdf to know more about USB DFU class.

Supported Combinations

Parameter Value
CPU + OS r5fss0-0 nortos
Toolchain ti-arm-clang
Boards am243x-evm, am243x-lp
Example folder examples/drivers/boot/sbl_dfu_uniflash

Steps to Run the Example

Since this is mainly a flash-writer application, this is sent via the USB DFU 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.

  • When using CCS projects to build, import the CCS project for the required combination and build it using the CCS project menu (see Using SDK with CCS Projects).
  • When using makefiles to build, note the required combination and build using make command (see Using SDK with Makefiles)

See Also


USB DFU Uniflash.

Flashing Tools

Flash a Hello World example using DFU

Sample Output

Since this SBL receives the appimage and other files over USB protocol, it doesn't print anything to the console.