User's Manual

UM2819
UM2819 - Rev 1
page 19/37
LEDs
7.5 LEDs
Six LEDs on the top side of the Nucleo board help the user during the application development.
Figure 12. LEDs location
ST Restricted
LD6 STLINK Status
LD1, user LED
LD4 STLink power fault LED
LD5 5V-enable LED
LD2, user LED
LD3, user LED
1. LD1: this blue LED is available for user application.
2. LD2: this green LED is available for user application.
3. LD3: this red LED is available for user application.
4. LD4: this LED turns red to indicate that the current distribution cannot be performed as expected when the
board is supplied by USB_STLINK.
5. LD5: this LED turns green when the 5V is available. To select the 5 V source, refer to Section 7.1.3 for
further details.
6. LD6 is a bi-color LED, which default status is red. It turns to green to indicate that communication is in
progress between the host PC and ST-LINK/V2-1 with the following steps:
– Slow blinking red and OFF: at power-on, before USB initialization
– Fast blinking red and OFF: after the first correct communication between the host PC and ST-LINK/
V2-1 (enumeration)
– Red ON: when initialization between the host PC and ST-LINK/V2-1 is successfully finished.
– Green ON: after successful target communication initialization
– Blinking red and green: during communication with the target
– Green ON: communication is successfully finished and OK.
– Orange ON: communication failure.