To Next Page

To Previous Page

UM2407 Rev 3 23/49

UM2407 Hardware layout and configuration

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

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

BUS

coming from STLINK-V3E might power the board, and

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)

Input power name Connector pins Voltage range Max current

3V3

CN8 pin 7

CN11 pin 16

3 V to 3.6 V 1.3 A

MSv61207V2

MSv61203V1

CN1

3V3

NO DEBUG

3V3

NO JUMPER

STMicroelectronics STM32H7 User Manual

Questions and Answers: