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UM1724 Rev 14 23/68

UM1724 Hardware layout and configuration

6.4 LEDs

The tricolor LED (green, orange, red) LD1 (COM) provides information about ST-LINK

communication status. LD1 default color is red. LD1 turns to green to indicate that

communication is in progress between the PC and the ST-LINK/V2-1, with the following

setup:

• Slow blinking Red/Off: at power-on before USB initialization

• Fast blinking Red/Off: after the first correct communication between the PC and

ST-LINK/V2-1 (enumeration)

• Red LED On: when the initialization between the PC and ST-LINK/V2-1 is complete

• Green LED On: after a successful target communication initialization

• Blinking Red/Green: during communication with the target

• Green On: communication finished and successful

• Orange On: Communication failure

User LD2: the green LED is a user LED connected to ARDUINO

signal D13 corresponding

to STM32 I/O PA5 (pin 21) or PB13 (pin 34) depending on the STM32 target. Refer to

Table 11 to Table 23 when:

• the I/O is HIGH value, the LED is on

• the I/O is LOW, the LED is off

LD3 PWR: the red LED indicates that the STM32 part is powered and +5V power is

available.

6.5 Push-buttons

B1 USER: the user button is connected to the I/O PC13 (pin 2) of the STM32

microcontroller.

B2 RESET: this push-button is connected to NRST, and is used to RESET the STM32

microcontroller.

Note: The blue and black plastic hats that are placed on the push-buttons can be removed if

necessary, for example when a shield or when an application board is plugged on top of the

Nucleo board. This will avoid pressure on the buttons and consequently a possible

permanent target STM32 RESET.

6.6 JP6 (IDD)

Jumper JP6, labeled IDD, is used to measure the STM32 microcontroller consumption by

removing the jumper and by connecting an ammeter:

• Jumper ON: STM32 microcontroller is powered (default).

• Jumper OFF: an ammeter must be connected to measure the STM32 microcontroller

current. If there is no ammeter, the STM32 microcontroller is not powered.

ST NUCLEO-F303RE User Manual

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