Mcu Voltage Selection: 1V8/3V3; Current Consumption Measurement (Idd); Virtual Com Port (Vcp): Lpuart/Usart; Table 10. Usart3 Connection - STMicroelectronics STM32H7 Nucleo-144 User Manual

UM2407
B2 RESET (black button): this push-button is connected to NRST and is used to reset the
STM32H7 Series microcontroller.
6.6.3

MCU voltage selection: 1V8/3V3

The STM32H7 Nucleo-144 board offers the possibility to supply the STM32H7 Series
microcontroller with 1.8 V or 3.3 V. JP5 is used to select the VDD_MCU power level.
•
Place the JP5 jumper on 3V3 to supply the MCU with 3V3, connecting pins 1 and 2.
•
Place the JP5 jumper on 1V8 to supply the MCU with 1V8, connecting pins 2 and 3.
6.6.4

Current consumption measurement (IDD)

Jumper JP4, labeled IDD, is used to measure the STM32H7 Series microcontroller
consumption by removing the jumper and by connecting an ammeter:
• JP4 ON: STM32H7 is powered with 3V3_VDD (default)
•
JP4 OFF: an ammeter must be connected to measure the STM32H7 current. If there is
no ammeter, the STM32H7 is not powered
Warning:
If needed, for low power measurement (for example standby mode), in order to measure
only MCU (U7) power consumption, the user must remove the following components: R4,
R43, R44, R45, R46, R47, R48, R49, R50, R51, R52, R53, R59, R61, U1, U10, U15 and
SB45.
After removing these components, it becomes impossible to use Ethernet, and 1.8 V debug
with ST-LINK.
6.6.5

Virtual COM port (VCP): LPUART/USART

The STM32H7 Nucleo-144 board offers the possibility to connect a LPUART or an USART
interface to the ST-LINK or to the ST morpho connectors and Arduino™ Uno V3 connectors.
The selection is done by settings the related solder bridges. (Refer to
below).
By default the USART3 communication between the target STM32H7 and the STLINK is
enabled, to support the Virtual COM port for the Mbed (SB5 and SB6 ON).
Pin
name
PD8
PD9
on MB1364 REV.C, "VDD_MCU" is also supplying Ethernet
PHY (U15) and debug voltage translation (U1 and U10).

Table 10. USART3 connection

Function
(default configuration)
USART3 TX SB5 ON and SB7 OFF
USART3 RX SB6 ON and SB4 OFF
Virtual COM port
UM2407 Rev 1
Hardware layout and configuration
Table 10
ST morpho connection
SB5 OFF and SB7 ON
SB6 OFF and SB4 ON
and Table 11
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