DHSBC-STM32MP13¶

Board Identification¶

Identifier: DHSBC-STM32MP13 719-300

Yocto MACHINE:

• dh-stm32mp13-dhcor-dhsbc-welma

Documentation:

• https://wiki.dh-electronics.com/index.php?title=DHSBC_STM32MP13
• DOC_DHSBC-STM32MP13-Quick-Start-Guide_R04_2025-04-08.pdf
• USM_DHCOR-STM32MP13_R02_2025-07-07.pdf

Features:

• MPU: STM32MP135f ARM Cortex‑A7 32-bit
• RAM: 512 MB
• Storage: 4GB eMMC, SPI NOR flash 4MB
• EEPROM 4 kB
• 1x USB Host type A, 2.0 high-speed
• 1x USB Device Type-C, 2.0 high-speed
• 2x Ethernet
• WiFi / Bluetooth

Glossary:

• FSBL: First Stage Boot Loader
• FIP: Container made by the Trusted Firmware-A package, that contains optee-os and u-boot
• SSBL: Second Stage Boot Loader
• TF-A: Trusted Firmware-A

Boot Sequence¶

The Welma boot sequence is as follows:

• ROM Code: loads BL2 (TF-A FSBL) from emmc's boot area partition, and starts it.
• BL2: loads the FIP image from the partition named "fip" (from eMMC user area) and starts:
  • OP-TEE (BL32)
  • U-Boot (BL33)
• U-Boot: starts the kernel
• The kernel mounts the initial ram file system (initramfs) and starts Init

First installation¶

• Connect USB-C DFU X2 connector of the board to your PC

• Connect FTDI TTL-232R-3V3 X9 connector to your PC, and open a terminal program on this serial console (bitrate 115200)

First Step: Get U-Boot running in RAM

• Switch boot mode to 123 = ON-ON-ON (USB DFU boot) (warning: depends on the hardware revision!)

• Power on or reset the board

• Start U-Boot through DFU

  $ cd $DEPLOY_DIR_IMAGE
  $ dfu-util -a 0 -D tf-a-stm32mp135f-dhcor-dhsbc.stm32-stm32mp1 -R
  $ dfu-util -a 0 -D fip.bin-stm32mp1 -R
  

• Interrupt U-Boot sequence and take control

Second Step: Install Welma on the eMMC using TFTP

• Have a TFTP server configured and started on your PC

• Connect the ETH1 X4 port to your PC

• Install BL2 to emmc's first boot area:

  STM32MP> setenv ipaddr 192.168.1.20
  STM32MP> setenv serverip 192.168.1.35
  
  STM32MP> tftpboot tf-a-stm32mp135f-dhcor-dhsbc.stm32-stm32mp1
  ...
  Load address: 0xc2000000
  Loading: ##################################################  78.5 KiB
           1.3 MiB/s
  ...
  
  STM32MP> setexpr nblocks $filesize + 0x1ff
  STM32MP> setexpr nblocks $nblocks / 0x200
  STM32MP> mmc dev 0 1
  STM32MP> mmc write $loadaddr 0 $nblocks
  MMC write: dev # 0, block # 0, count 157 ... 157 blocks written: OK
  

• Set the emmc to boot from emmc's first boot area:

  STM32MP> mmc partconf 0 1 1 0
  
  STM32MP> mmc partconf 0
  EXT_CSD[179], PARTITION_CONFIG:
  BOOT_ACK: 0x1
  BOOT_PARTITION_ENABLE: 0x1 (boot0)
  PARTITION_ACCESS: 0x0 (user)
  

• Install FIP, kernel and filesystems to emmc's user area:

STM32MP> setenv ipaddr 169.254.142.1; setenv serverip 169.254.142.224;
STM32MP> tftpboot demo-image-headless-dev-dh-stm32mp13-dhcor-dhsbc-welma.wic.gz
STM32MP> gzwrite mmc 0 $loadaddr $filesize

Regular Boot¶

The regular boot on a SD card is done as follows:

• Switch boot mode to 1-2-3 = OFF-ON-OFF (warning: depends on the hardware revision!)

• Reset or start the board

Appendix¶

Connecting the board¶

• X1: USB Type-C Power supply
• X2: USB Type-C for DFU and UMS data connection
• X4: Ethernet ETH1
• X9: Serial console, baud rate 115200. Use FTDI cable TTL-232R-3V3.
• S3: Boot switch mode, see next section

Boot mode switch S3¶

Boot from SPI NOR flash¶

If, instead of booting from emmc, you want the board to boot from the SPI NOR flash, this section explains how to install and start.

• Prerequisites:

  • Have a running U-Boot on the board (see First Installation)

• (optional) Erase the SPI NOR flash (takes about 1 min)

  STM32MP> mtd erase nor0
  Erasing 0x00000000 ... 0x003fffff (1024 eraseblock(s))
  

• Install bootloader to SPI NOR flash:

U-Boot side:

STM32MP> sf probe
STM32MP> env set dfu_alt_info "mtd nor0=fsbl1 raw 0x0 0x40000;fip raw 0x80000 0x160000"
STM32MP> dfu 0 mtd

Host PC side:

$ dfu-util -a 0 -D tf-a-stm32mp135f-dhcor-dhsbc.stm32-stm32mp1
$ dfu-util -a 1 -D fip.bin-stm32mp1

• Switch boot mode to 1-2-3 = ON-OFF-OFF (depends on the hardware revision!)

• Power cycle the board

Hardware watchdog¶

The hardware watchdog is:

• Started by U-Boot (timeout 32 s)
• Serviced by the Linux kernel (as long as no userspace process opens /dev/watchdog0 and takes over)
• Then serviced by systemd

/sys/class/watchdog/watchdog0 -> ../../devices/platform/soc/5a002000.watchdog/watchdog/watchdog0

Fusing ethernet MAC addresses in OTP¶

When boards are not provisioned with ethernet MAC addresses, U-Boot assigns random values at each boot, and this is generally not what we need.

This section explains how to fix these MAC addresses by writing fixed values in OTP registers.

• Read MAC addresses registers:

  STM32MP> fuse sense 0 0x39 3
  Sensing bank 0:
  
  Word 0x00000039: 00000000 00000000 00000000
  

• Program MAC addresses:

  STM32MP> fuse prog -y 0 0x39 3d62b4e6 265a67d5 6984c430
  Programming bank 0 word 0x00000039 to 0x3d62b4e6...
  Programming bank 0 word 0x0000003a to 0x265a67d5...
  Programming bank 0 word 0x0000003b to 0x6984c430...
  

• Lock MAC addresses:

  STM32MP> fuse prog -y 0 0x10000039 0x40000000 0x40000000 0x40000000
  

• Check:

  STM32MP> fuse sense 0 0x39 3
  Sensing bank 0:
  
  Word 0x00000039: 3d62b4e6 265a67d5 6984c430
  
  
  STM32MP> fuse sense 0 0x10000039 3
  
  Sensing bank 0:
  
  Word 0x10000039: 40000000 40000000 40000000
  
  STM32MP> reset
  ...
  
  STM32MP> printenv
  ...
  eth1addr=5a:26:30:c4:84:69
  ethaddr=e6:b4:62:3d:d5:67
  ...
  

  Ref: https://wiki.st.com/stm32mpu/wiki/How_to_update_OTP_with_U-Boot