Debugging While Using Vin Or Ext As An External Power Supply; Table 9. External Power Sources: 3V3_Ext (3.3 V); Figure 14. Power Supply Input From 3V3_Ext (3.3 V) - STMicroelectronics STM32H7 User Manual

UM2407
Input power name
CN1
6.4.6

Debugging while using VIN or EXT as an external power supply

When powered by VIN or EXT, it is still possible to use the STLINK-V3E for programming or
debugging only. In this case, it is mandatory to power the board first using VIN or EXT, then
to connect the USB cable to the PC. In this way, the enumeration succeeds, thanks to the
external power source.
The following power-sequence procedure must be respected:
1. Configure the JP2 jumper [5-6] for EXT or [3-4] for VIN.
2. Connect the external power source to VIN or EXT.
3. Power on the external power supply 7 V < VIN < 12 V to VIN, or 5 V for EXT.
4. Check that the green LED (LD5) is turned ON.
5. Connect the PC to the USB connector (CN1).
If this order is not respected, V
the following risks might be encountered:
1. If the board needs more than 300 mA current, the PC might be damaged, or the PC
can limit the supplied current. As a consequence, the board is not powered correctly.
2. 300 mA is requested during enumeration. So, there is a risk that the request is rejected
and the enumeration does not succeed if the PC cannot provide such current.
Consequently, the board is not power-supplied. The green LED (LD5) remains OFF.

Table 9. External power sources: 3V3_EXT (3.3 V)

Connector pins
CN8 pin 7
3V3
CN11 pin 16

Figure 14. Power supply input from 3V3_EXT (3.3 V)

3V3
Voltage range
3 V to 3.6 V
NO DEBUG
3V3
MSv61203V1
U2
coming from STLINK-V3E might power the board, and
BUS
UM2407 Rev 3
Hardware layout and configuration
Max current
1.3 A
MSv61207V2
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