Hardware and layout
UM1656
16/30
DocID025091 Rev 1
4.3
Power supply and power selection
The power supply is provided either by the host PC through the USB cable, or by an
external 5V power supply.
The D1 and D2 diodes protect the 5V and 3V pins from external power supplies:
•
5V and 3V can be used as output power supplies when another application board is
connected to pins P1 and P2.
In this case, the 5V and 3V pins deliver a 5V or 3V power supply and power
consumption must be lower than 100 mA.
•
5V can also be used as input power supplies e.g. when the USB connector is not
connected to the PC.
In this case, the 32L100CDISCOVERY board must be powered by a power supply unit
or by auxiliary equipment complying with standard EN-60950-1: 2006+A11/2009, and
must be Safety Extra Low Voltage (SELV) with limited power capability.
4.4 LEDs
•
LD1 PWR: Red LED indicates that the board is powered.
•
LD2 COM: Tricolor LED (COM) advises on the communication status as follows:
–
Slow blinking Red LED/Off: At power on before USB initialization
–
Fast blinking Red LED/Off: After the first correct communication between PC and
STLINK/V2 (enumeration)
–
Red LED On: When initialization between PC and ST-LINK/V2 is successfully
finished
–
Green LED On: After successful target communication initialization
–
Blinking Red/Green LED: During communication with target
–
Red LED On: Communication finished and OK
–
Orange LED On: Communication failure
•
User LD3: Green user LED connected to the I/O PC9 of the STM32L100RCT6.
•
User LD4: Blue user LED connected to the I/O PC8 of the STM32L100RCT6.
4.5 Push
buttons
•
B1 USER: User push button connected to the I/O PA0 of the STM32L100RCT6.
•
B2 RESET: Push button used to RESET the STM32L100RCT6.
4.6 JP2
(I
DD
)
Jumper JP2, labeled I
DD
, allows the consumption of STM32L100RCT6 to be measured by
removing the jumper and connecting an ammeter.
•
Jumper on: STM32L100RCT6 is powered (default).
•
Jumper off: an ammeter must be connected to measure the STM32L100RCT6 current,
(if there is no ammeter, the STM32L100RCT6 is not powered).
