Oscillators - mikroElektronika mikromedia for STM32 Manual

5. Oscillators

STM32F207VGT6 STM32F407VGT6
and
microcontrollers are equipped with internal
16MHz RC oscillator that provides stable clock
signal. Since the chips have an integrated PLL, this
base frequency is suitable for further clock multiplication.
Board also contains 32.768kHz Crystal oscillator (X1)
which provides external clock for internal
C41 2.2uF
R65
100K
51
PB12
52
PB13
53
PB14
54
PB15
55
PD8
56
PD9
57
PD10
58
PD11
59
PD12
60
PD13
61
PD14
62
STM32F207VGT6
PD15
63
PC6
64
STM32F407VGT6
PC7
65
PC8
66
PC9
67
PA8
68
PA9
69
PA10
70
PA11
71
PA12
72
PA13
73
VCAP
74
GND
75
VDD
C42
2.2uF
RTCC
module.
VCC-3.3
Figure 5-2:
AVCC
Crystal oscillator
schematics
U1
25
VREF-1.8
PA2
24
PA1
23
PA0-WKUP
VCC-3.3
22
VDDA
21
VREF+
20
GNDA
19 J3
VDD
18
PC3
17
PC2
16 J2
PC1
15
PC0
14
NRST
13
OSC_OUT
12
OSC_IN
11
VDD
10
GND
9 OSC32_OUT
PC15/OSC32_OUT
8 OSC32_IN X1
PC14/OSC32_IN
7
PC13/TAMPER_RTC
6
VBAT
5 32.768KHz
PE6
4 C1 C2
PE5
22pF 22pF
3
PE4
2
PE3
1
PE2
NOTE:
R66 100K
VCC-3.3 VCC-3.3 VCC-3.3 VCC-3.3 VCC-3.3 VCC-3.3
E8 C5 C6 C7 C8 C31
10uF 100nF 100nF 100nF 100nF 100nF
decoupling
capacitors
Figure 5-1:
Crystal oscillator module (X1)
The use of crystal in all other schematics is implied even if it is
purposely left out, because of the schematics clarity.
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