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This application note explains how to install the U-Boot firmware to the STM32H7 SOM. Refer to Understanding STM32H7 SOM Boot Architecture (uClinux) as a pre-requisite to understanding the installation procedure.

1. Hardware Set-Up

The following hardware set-up is required for installation of the software to the STM32H7 SOM:

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NOTE: The STM32H7-BSB Rev 1A/2A baseboards are supported by BSP version 2.5.0. The newer versions support the STM32H7-BSB Rev 4A baseboard only.

2. Installable Images

The images to be installed onto the STM32H7 SOM can be obtained using one of the two approaches, as follows:

• Build the images from the sources, as documented in: Building and selfSelf-updating U-Boot on the STM32H7 SOM (uClinux) .

• Use the prebuilt images and the Kermit script provided by Emcraft.

3. Installing U-Boot SPL to Internal Flash

Step through the following procedure to install the U-Boot SPL to the internal Flash of the STM32H750:

1. Run the following command on the Linux development host:

   Code Block

   [root@workbench linux-cm-stm32h7-2.6.1]# st-flash write u-boot/spl/\ u-boot-spl.bin 0x08000000 st-flash 1.7.0-120-gbeffed4 2024-05-03T05:15:24 INFO common.c: H74x/H75x: 128 KiB SRAM, 22633 KiB flash in at least 128 KiB pages. file u-boot-spl.bin md5 checksum: d4d01d8f8aa453144bbe499de1181, stlink checksum: 0x0050b4bb 2024-05-03T05:15:24 INFO common.c: Attempting to write 61229 (0xef2d) bytes to stm32 address: 134217728 (0x8000000) 2024-05-03T05:15:24 WARN common.c: unaligned len 0xef2d -- padding with zero 2024-05-03T05:15:25 INFO common.c: Flash page at addr: 0x08000000 erased 2024-05-03T05:15:25 INFO common.c: Finished erasing 1 pages of 131072 (0x20000) bytes 2024-05-03T05:15:25 INFO common.c: Starting Flash write for H7 61230/61230 bytes written 2024-05-03T05:15:27 INFO common.c: Starting verification of write complete 2024-05-03T05:15:27 INFO common.c: Flash written and verified! jolly good! [root@workbench linux-cm-stm32h7-2.6.1]#

2. Verify that the U-Boot SPL has been successfully installed. Reset the SOM by pressing the S3 button on the carrier board and confirm that the following output appears on the serial UART console:

   Code Block
   U-Boot SPL 2019.04- (May 03 2024 - 06:09:05 +0000) Hit 's' key to enter spl shell: Trying to boot from SPI

4. Installing U-Boot "Proper" to QSPI Flash

Step through the following procedure to install the U-Boot "Proper" to the QSPI Flash:

1. On the development host, make sure that your serial terminal utility (such as picocom) is not connected to the board serial console (/dev/ttyUSB1 in this example). Exit the utility or just kill it, for example:

   Code Block
   [sasha_d@workbench ~]$ killall picocom [sasha_d@workbench ~]$

2. Run the following command on the Linux development host:

   Code Block
   [sasha_d@workbench linux-cm-stm32h7-2.6.1]$ ./u-boot/board/emcraft/stm32h7-som/stm32h7-som-uboot-install.kermit /dev/ttyUSB1 u-boot/u-boot.img

3. Reset the target board to start programming u-boot/u-boot.img via /dev/ttyUSB1.

4. Reset the SOM by pressing the S3 button on the carrier board.

5. Wait for the kermit utility to load the U-Boot image (observe the progress indicators).

6. The script will exit successfully at the end of the installation procedure:

   Code Block
   ... Successfully programmed u-boot/u-boot.img to SPI Flash ... STM32H7-SOM U-Boot > ubi create env1 0x8000 Creating dynamic volume env1 of size 32768 STM32H7-SOM U-Boot > ubi create env2 0x8000 Creating dynamic volume env2 of size 32768 STM32H7-SOM U-Boot > [sasha_d@workbench linux-cm-stm32h7-2.6.1]$

7. Connect to the SOM console using a serial terminal utility, for example:

   Code Block
   [sasha_d@workbench ~]$ picocom -b 115200 /dev/ttyUSB1

8. Verify that the U-Boot "proper" has been successfully installed. Reset the SOM by pressing the S3 button on the carrier board and confirm that the following output appears on the serial UART console:

   Code Block

   U-Boot SPL 2019.04- (May 03 2024 - 06:09:05 +0000) Hit 's' key to enter spl shell: Trying to boot from SPI U-Boot 2019.04- (May 03 2024 - 06:09:05 +0000) Model: STMicroelectronics STM32H7 SOM DRAM: 32 MiB SF: Detected n25q512ax3 with page size 256 Bytes, erase size 4 KiB, total 64 MiB Flash: 128 KiB MMC: STM32 SDMMC2: 0 Loading Environment from UBI... ubi0: default fastmap pool size: 256 ubi0: default fastmap WL pool size: 128 ubi0: attaching mtd2 ubi0: scanning is finished ubi0: attached mtd2 (name "system", size 31 MiB) ubi0: PEB size: 4096 bytes (4 KiB), LEB size: 3968 bytes ubi0: min./max. I/O unit sizes: 1/256, sub-page size 1 ubi0: VID header offset: 64 (aligned 64), data offset: 128 ubi0: good PEBs: 7936, bad PEBs: 0, corrupted PEBs: 0 ubi0: user volume: 4, internal volumes: 1, max. volumes count: 23 ubi0: max/mean erase counter: 2/1, WL threshold: 4096, image sequence number: 0 ubi0: available PEBs: 1518, total reserved PEBs: 6418, PEBs reserved for bad PEB handling: 0 Read 16384 bytes from volume env1 to d196f520 Read 16384 bytes from volume env2 to d1973540 *** Warning - bad CRC, using default environment In: serial Out: serial Err: serial Volume splash not found! splash_screen_display: ubi_volume_read error=19 Net: Error: ethernet@40028000 address not set. eth-1: ethernet@40028000 Hit any key to stop autoboot: 0 ERROR: Active image set is invalid STM32H7-SOM U-Boot >

5. Enabling LCD and Splash Screen on Starter Kit with LCD

If your starter kit includes the LCD, it can be enabled in software by installing the U-Boot splash screen image to the QSPI Flash. Step through the following procedure to install the stm32h7-splash-24bpp.bmp picture as the splash screen:

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