OLIMEX© 2018
STM32-H407 user's manual
CHAPTER 5 CONTROL CIRCUITY AND HARDWARE MODULES
5. Introduction to the chapter
Here you can find information about reset circuit and quartz crystals locations, the power supply
circuit is discussed.
5.1 Reset
STM32-H407's reset circuit includes R21 (10KΩ), R19 (1 KΩ), C35 (100nF) and a RESET button.
5.2 Clocks
There are two quartz crystals available on the board:
12 MHz quartz crystal Q1 is connected to pins 23 and 24 of the CORTEX-M4F processor.
Quartz crystal Q2 is a 32 768Hz RTC (real-time clock) and is connected to pins 8 and 9.
5.3 Power supply circuit
The power supply circuit of STM32-H407 allows flexible input supply from 6V to 16V direct
current. This means a wide range of power supplies, adapters, converters are applicable. The
maximum amperage the board can draw is 1A.
The Li-Po battery connector cannot be used to fully power the board. Its function is to give an
option to save internal data if the board needs to be relocated. It will keep the RTC alive, for
instance.
If you have successfully powered the board the red PWR LED will turn on. Note that it is possible
to have the PWR LED on even if there isn't enough power for proper operation of the board and all
the peripherals currently connected.
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