Table 30. Low-Speed External User Clock Characteristics; Figure 13. High-Speed External Clock Source Ac Timing Diagram; Figure 14. Low-Speed External Clock Source Ac Timing Diagram - STMicroelectronics STM32F038C6 Manual

STM32F038x6
Low-speed external user clock generated from an external source
In bypass mode the LSE oscillator is switched off and the input pin is a standard GPIO.
The external clock signal has to respect the I/O characteristics in
the recommended clock input waveform is shown in
Symbol
f
LSE_ext
V
LSEH
V
LSEL
t
w(LSEH)
t
w(LSEL)
t
r(LSE)
t
f(LSE)
1. Guaranteed by design, not tested in production.

Figure 13. High-speed external clock source AC timing diagram

Table 30. Low-speed external user clock characteristics

Parameter
User external clock source frequency
OSC32_IN input pin high level voltage
OSC32_IN input pin low level voltage
OSC32_IN high or low time
OSC32_IN rise or fall time

Figure 14. Low-speed external clock source AC timing diagram

DocID026079 Rev 3
Figure
(1)
Min
-
0.7 V
DDIOx
V
SS
450
-
Electrical characteristics
Section 6.3.13. However,
14.
Typ Max
32.768 1000
- V
DDIOx
- 0.3 V
DDIOx
- -
- 50
Unit
kHz
V
ns
53/102
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