Board Power Supply - Vdd50_Usb And Vregoutv33V; Table 12. Usb Power Sources; Figure 16. Mcu Power: Usb Regulator; Figure 17. Vdd50_Usb And Vregoutv33V Schematic - STMicroelectronics STM32H7B3I-EVAL User Manual

Caution: A deadlock occurs if the board SMPS/LDO firmware PWR configuration does not match its hardware
configuration: after the reset, ST-LINK cannot connect to the target anymore.
The firmware PWR configuration must be set as follows in the SystemClock_Config function in the
file:
• If the hardware configuration is Direct SMPS (default configuration):
HAL_PWREx_ConfigSupply(PWR_DIRECT_SMPS_SUPPLY);
• If the hardware configuration is LDO:
HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);
If a deadlock occurs because of a mismatch between hardware and firmware PWR settings (SMPS/LDO), the
user can recover the board by applying the following procedure:
1. Power off the board.
2. Set SW1 (BOOT0) to 1 (system memory).
This changes the BOOT0 pin to 1 instead of 0. Thus, changing the device boot address to boot address 1
and making the bootloader start in system memory. This avoids starting firmware in the user flash with a
wrong SMPS/LDO configuration versus the hardware board configuration.
3. Power on the board and connect using STM32CubeProgrammer (STM32CubeProg).
4. Erase the user flash.
5. Power off the board and set SW1 to 0.
6. The board is recovered and can be used normally with matching PWR firmware.
6.5.4

Board power supply - VDD50_USB and VREGOUTV33V

The USB power sources to the STM32H7B3LIH6Q microcontroller can be selected by setting solder bridges as
shown in Table
1. The default setting is in bold.
UM2662 - Rev 4
Figure 16.
12:
Figure 17. VDD50_USB and VREGOUTV33V schematic (page 21)
Table 12.
(1)
Power mode
External USB supply
USB regulator supply
MCU power: USB regulator
USB power sources
Mount
SB16, SB17
SB18
UM2662
Hardware layout and configuration
main.c
Unmount
SB18
SB16, SB17
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