CD00237391 Datasheet, PDF (82/177 Pages) STMicroelectronics – ARM-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM

Electrical characteristics
Figure 28. High-speed external clock source AC timing diagram
STM32F20xxx
VH_SEH
90%
10%
VH_SEL
tr(H_SE)
tf(H_SE)
TH_SE
tW(H_SE)
tW(H_SE) t
External
clock source
fH_{SE_ext}
OSC _IN
IL
STM32F
Figure 29. Low-speed external clock source AC timing diagram
ai17528
VL_SEH
VL_SEL
90%
10%
tr(L_SE)
tf(L_SE)
TL_SE
tW(L_SE)
tW(L_SE) t
External
clock source
fL_{SE_ext}
OSC32_IN
IL
STM32F
ai17529
High-speed external clock generated from a crystal/ceramic resonator
The high-speed external (HSE) clock can be supplied with a 4 to 26 MHz crystal/ceramic
resonator oscillator. All the information given in this paragraph are based on characterization
results obtained with typical external components specified in Table 28. In the application,
the resonator and the load capacitors have to be placed as close as possible to the oscillator
pins in order to minimize output distortion and startup stabilization time. Refer to the crystal
resonator manufacturer for more details on the resonator characteristics (frequency,
package, accuracy).
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Doc ID 15818 Rev 9