How to load and start STM32CubeMP13 applications via microSD card

Applicable for

STM32MP13x lines

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This article explains how to load and start STM32CubeMP13 applications via microSD^™ card using the "SD external loader firmware utility" provided with the STM32CubeMP13 package. This use case is useful in production mode.

1. SD external loader firmware utility

1.1. Introduction

The SD external loader firmware utility is used to load and start STM32CubeMP13 applications programmed into a microSD^TM card.

• It allows the programming of embedded software applications on external microSD^TM cards for the STM32MP135x-DK Discovery kit .
• This package contains all the binaries necessary to program the microSD^TM card through the serial interface and boot from the microSD^TM card.
• This package version :
  • Supports the UART serial protocol.
  • Does not support the USB DFU serial protocol in this release.
  • Does not support OTP programming.

Information

The utility source code can be requested from the STMicroelectronics support teams for use as an example, and is easily adapted for customer boards.

1.2. Contents

The SD External Loader utility contains the binaries listed below, as well as readme and .tsv files. Details for each can be found below.

├── Projects
    ├── STM32MP135C-DK
       ├── External_Loader
          ├── SD_Ext_Loader
          │    ├── [FlashLayout_OpenBL_ExtLoaderSDMMC_SerialBoot.tsv]
          │    ├── [FSBLA_Sdmmc1_A7_Signed.bin]
          │    ├── [MP13_BSP_TemplatesA7_DISCO_Signed.bin]
          │    ├── [readme.txt]
          │    ├── [SD_Ext_Loader.bin]
          │    ├── [STM32PRGFW_UTIL_MP13xx_CP_Serial_Boot.stm32]

• FlashLayout_OpenBL_ExtLoaderSDMMC_SerialBoot.tsv
  

This file defines flash memory partitions, binaries, and the corresponding partition ID. Refer to the STM32CubeProgrammer_flashlayout article for more details.

• FSBLA_Sdmmc1_A7_Signed.bin

This binary is the first-stage bootloader (FSBLA), programmed via STM32PRGFW_UTIL_MP13xx_CP_Serial_Boot.stm32 on the microSD^TM card, and is used to load the test application from the microSD^™ card to DDR.

• MP13_BSP_TemplatesA7_DISCO_Signed.bin

This binary is the test application, programmed on the microSD^™ card via STM32PRGFW_UTIL_MP13xx_CP_Serial_Boot.stm32. On reset, when booting from the microSD^™ card, it is loaded into DDR for execution by FSBLA.

This can be replaced with any customer test application. Application has to be built for DDR (refer to build test application for DDR) and then properly signed with the STM32CubeProgrammer signing tool (or via postbuild steps and scripts)). In this test application, the blue LED is initialized and after successful execution, the blue LED is toggled at 200ms and the logs shown below are printed on the serial console:

• readme.txt

Read this file carefully; it provides all the information for the example setup and verdict.

• SD_Ext_Loader.bin

This binary provides microSD^™ card read, write, and erase functionalities. It is used for programming binaries onto the microSD^™ card.

• STM32PRGFW_UTIL_MP13xx_CP_Serial_Boot.stm32

This binary initializes the UART interface and reads binaries serially in serial boot mode.

SD_Ext_Loader.bin is loaded into RAM. FSBLA_Sdmmc1_A7_Signed.bin and MP13_BSP_TemplatesA7_DISCO_Signed.bin are programmed into the microSD^™ card for subsequent boot in SD mode. Refer to Set boot switches for more details.

2. Hardware and software prerequisites

• STM32MP135x-DK Discovery kit with a micro-USB cable connected to the ST-Link port.
• USB Type-C cable for powering the board.
• A microSD^™ card plugged into the microSD^™ card slot in the board.
• STM32CubeProgrammer PC tool installed (v2.14.0 minimum).

3. How to run the utility

3.1. Set boot mode to serial

• Set the boot pins to the b000 (BOOT0/1/2 to OFF) position to select serial mode. Refer to Set boot switches.
  
• Connect the micro-USB cable between the PC and ST-Link connector on the board. The PC should detect the UART interface.

Important

ST-Link provides a UART interface via Virtual COM port on the board, like STM32MP135x-DK Discovery kit .

Warning

ROM CODE gives preference to USB DFU if the USB cable is connected to other places than the ST-Link USB port. If you want to use UART, the USB cable should NOT be connected to any other ports on the board than ST-Link USB.

3.2. Program the microSD^™ card in serial boot

3.2.1. Program the microSD^™ card using the STM32CubeProgrammer GUI

Read the STM32CubeProgrammer articles for more details.

• Click on UART and then select COM port:
  

• Click on the Connect button:
  

STM32CubeProgrammer is now connected to ROM Code and the logs show the chip ID, bootloader version, and other details.

• Click on on the "+" icon, then on Open file and select "TSV file": FlashLayout_OpenBL_ExtLoaderSDMMC_SerialBoot.tsv

• Select the Binaries path with the Browse button (Firmware\Projects\STM32MP135C_DK\External_Loader\SD_Ext_Loader):
  

• Click on the Download button:
  

STM32CubeProgrammer now starts downloading the binaries. Once they've been successfully downloaded, a pop-up message indicates Flashing service completed successfully.

3.2.2. Program the microSD^™ card using the STM32CubeProgrammer CLI

• Browse to the installed STM32CubeProgrammer binary directory (STM32CubeProgrammer\bin).
• Open a command prompt from this directory.
• Execute the command command to load the SD external loader binaries:

$STM32_Programmer_CLI.exe -c port=COM 
<num> -w 
<YourDirectoryPath>\Projects<STM32device>\External_Loader\SD_Ext_Loader\FlashLayout_OpenBL_ExtLoaderSDMMC_SerialBoot.tsv

• DO NOT reset the board until the command has been fully completed.
• STM32CubeProgrammer now starts downloading all binaries listed in the TSV file. When all binaries have been downloaded successfully, a message indicates Flashing service completed successfully.

3.3. Run the test application

• When the binaries have been programmed onto the microSD^™ card successfully, set the boot pins to the b101 (BOOT0 and BOOT2 to ON and BOOT1 to OFF) position to select SD mode. Refer to Set boot switches for more details.
  
• The MP13_BSP_TemplatesA7_DISCO_Signed.bin test application toggles the blue LED at 200ms, indicating that it has been loaded and executed successfully from DDR. It also prints the following logs on the serial console:
  

Secure digital

Universal asynchronous receiver/transmitter

Device firmware upgrade

One time programmed

Board support package

Discovery kit

Doubledata rate (memory domain)

Light-emitting diode

Random access memory (Early computer memories generally hadserial access. Memories where any given address can be accessed when desired were then called "random access" to distinguish them from the memories where contents can only be accessed in a fixed order. The term is used today for volatile random-acces ssemiconductor memories.)

spelling for older versions of STLink, ST in-circuit debugger and programmer for the STM8 and STM32 microcontroller families

USB port or connector

Read only memory

Graphical user interface