Osc Clock; Osc Clock Supply; Osc 32 Khz Clock Supply - ST STM32F4DISCOVERY User Manual

UM1472
4.10

OSC clock

4.10.1

OSC clock supply

If PH0 and PH1 are only used as GPIOs instead of as a clock, then SB13 and SB14 are
closed and R24, R25 and R68 are removed.
•
MCO from ST-LINK. From MCO of the STM32F103. This frequency cannot be
changed, it is fixed at 8 MHz and connected to PH0-OSC_IN of the STM32F407VGT6.
Configuration needed:
–
–
–
•
Oscillator onboard. From X2 crystal. For typical frequencies and its capacitors and
resistors, please refer to the STM32F407VGT6 Datasheet. Configuration needed:
–
–
–
• Oscillator from external PH0. From external oscillator through pin 7 of the P2
connector. Configuration needed:
–
–
–
4.10.2

OSC 32 KHz clock supply

If PC14 and PC15 are only used as GPIOs instead of as a clock, then SB15 and SB16 are
closed, and R21 and R22 are removed.
• Oscillator onboard. From X1 Crystal (not provided). Configuration needed:
–
–
•
Oscillator from external PC14. From external oscillator trough the pin 9 of P2
connector. Configuration needed:
–
–
–
a. As the frequency supplied by X2 is the same as MCO (8 MHz) R25 and R68 are soldered.
SB13, SB14 OPEN
(a)
R25 removed
(a)
R68 soldered
SB13, SB14 OPEN
(a)
R25 soldered
(a)
R68 removed
SB13 closed
SB14 closed
R25 and R68 removed
SB15, SB16 OPEN
C16, C27, R21 and R22 soldered.
SB16 closed
SB15 closed
R21 and R22 removed
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Hardware and layout
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