STM32L151C8T6 Datasheet, PDF (85/121 Pages) STMicroelectronics – Ultra-low-power 32-bit MCU ARM-based Cortex-M3, 128KB Flash, 16KB SRAM, 4KB EEPROM, LCD, USB, ADC, DAC

STM32L151x6/8/B, STM32L152x6/8/B
Electrical characteristics
Figure 20. I²C bus AC waveforms and measurement circuit
VDD
VDD
I²C bus
4 .7 k
4 .7 k
STM32L15xxx
100
SDA
100
SCL
SD A
tf(SDA)
S TART
S TART REPEATED
tsu(STA)
S TART
tr(SDA)
tsu(SDA)
th(STA)
tw(SCKL)
th(SDA)
S TOP
tsu(STA:STO)
SCL
tw(SCKH)
tr(SCK)
tf(SCK)
tsu(STO)
ai17855
1. Measurement points are done at CMOS levels: 0.3V_DD and 0.7V_DD.
Table 48.
SCL frequency (f_PCLK1= 32 MHz, V_DD = 3.3 V)⁽¹⁾⁽²⁾
f_SCL (kHz)
I2C_CCR value
R_P = 4.7 kΩ
400
0x801B
300
0x8024
200
0x8035
100
0x00A0
50
0x0140
20
0x0320
1. R_P = External pull-up resistance, f_SCL = I²C 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 is ±2%. These variations depend on the accuracy of the external
components used to design the application.
Doc ID 17659 Rev 8
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