ST STM32H743I-EVAL User Manual page 14

Hardware layout and configuration
Note:
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host PC. If the host is able to provide the required power, the enumeration succeeds, the
power transistor U19 (ST890) is switched ON, the red LED LD9 is turned ON, and thus the
STM32H743I-EVAL board is powered and can consume maximum 300 mA current. If the
host PC is not able to provide the requested current, the enumeration fails. Therefore the
STM32 part including the extension board is not powered. As a consequence the red LED
LD9 remains turned OFF. In this case it is mandatory to use an external power supply to
supply extra power.
E5V (from PSU) or D5V can be used as an external power supply in case the current
consumption of the STM32H743I-EVAL board exceeds the allowed current on USB. In this
condition it is still possible to use USB for communication, programming or debugging only,
but it is mandatory to power the board first using E5V or D5V, and then connecting the USB
cable to the PC. Proceeding this way ensures that the enumeration succeeds thanks to the
external power source.
The following power sequence procedure must be respected:
1. Connect jumper JP10 for PSU or D5V side
2. Check that JP15 is removed
3. Connect the external power source to PSU or D5V (daughterboard mounted)
4. Check red LED LD9 is turned ON
5. Connect the PC to USB connector CN23
If this order is not respected, the board may be powered by V
and the following risks may be encountered:
1. If more than 300 mA current is needed by the board, the PC may be damaged or
current can be limited by PC. As a consequence the board is not powered correctly.
2. 300 mA is requested at the enumeration phase (since JP15 must be OFF), so there is
risk that the request is rejected and the enumeration does not succeed if PC cannot
provide such current. Consequently the board is not powered (LED LD9 remains OFF).
In case the STM32H743I-EVAL board is powered by a USB charger, there is no USB
enumeration, so the led LD9 remains set to OFF permanently and the board is not powered.
Only in this specific case the jumper JP15 needs to be set to ON, to allow the board to be
powered anyway.
The power supply is configured by setting the related jumpers JP9, JP10 and JP11 as
described in Table 3.
DocID030511 Rev 1
UM2198
first then by E5V or D5V,
BUS