UM1956 Rev 5
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UM1956
Hardware layout and configuration
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6.7 JP1
(IDD)
JP1, labeled IDD, is used to measure the STM32 microcontroller consumption by removing
the jumper and connecting an ammeter:
•
JP1 on: STM32 is powered (default)
•
JP1 off: an ammeter must be connected to measure the STM32 current
If there is no ammeter, STM32 is not powered.
6.8 OSC
clock
U2 pin 2 and pin 3 can be used as OSC clock input or as Arduino Nano D8 and D7 GPIO.
There are four ways to configure the pins corresponding to different STM32 and clock usage
(refer to
).
Table 6. OSC clock configurations
Solder bridge
STM32
Clock configuration
SB4
SB17
SB6
SB8
SB5 and
SB7
ON
OFF
OFF
ON
OFF
STM32Fxxx
MCO from ST-LINK
connected to OSCIN
(PF0)
(1)
1. In applications where VCP is used for communication at a speed higher than 9600 bauds, it may be
needed to use this solder bridge configuration, to use 8 MHz clock (MCO from ST-LINK) and get a more
precise frequency.
OFF
OFF
ON
ON
OFF
HSI configuration
(default configuration)
OFF
ON
OFF
OFF
OFF
STM32Lxxx
MCO from ST-LINK
connected to CKIN
(PA0)
OFF
OFF
OFF
OFF
ON
32K LSE mounted on X1
(default configuration)
OFF
OFF
ON
ON/OFF
OFF
All
Arduino Nano D7
connected to PF0 / PC14
OFF
OFF
ON/OFF
ON
OFF
Arduino Nano D8
connected to PF1 / PC15
Boards with STM32Lxxx are delivered with 32.768 KHz crystal (X1). Associated capacitors
and solder bridges (C12, C13 and SB4 to SB8) are configured to support LSE by default.
Boards with STM32Fxxx are delivered without crystal (X1). Associated capacitors (C12,
C13) are not populated and SB4 to SB8 are configured to support HSI by default.
