Datasheet

DS5792 Rev 13 97/143
STM32F103xC, STM32F103xD, STM32F103xE Electrical characteristics
135
Figure 48. I
2
C bus AC waveforms and measurement circuit
1.
Measurement points are done at CMOS levels: 0.3V
DD
and 0.7V
DD.
2. Rs: Series protection resistors.
3. Rp: Pull-up resistors.
4. VDD_I2C : I2C bus supply
Table 52. SCL frequency (f
PCLK1
= 36 MHz.,V
DD_I2C
= 3.3 V)
(1)(2)
1. R
P
= External pull-up resistance, f
SCL
= I
2
C speed.
2. For speeds around 200 kHz, the tolerance on the achieved speed is of ±5%. For other speed ranges, the
tolerance on the achieved speed ±2%. These variations depend on the accuracy of the external
components used to design the application.
f
SCL
(kHz)
I2C_CCR value
R
P
= 4.7 kΩ
400 0x801E
300 0x8028
200 0x803C
100 0x00B4
50 0x0168
20 0x0384
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