STM32F405XX_13 Datasheet, PDF (118/185 Pages) STMicroelectronics – ARM Cortex-M4 32b MCU+FPU, 210DMIPS, up to 1MB Flash/192+4KB RAM, USB OTG HS/FS

Electrical characteristics
STM32F405xx, STM32F407xx
Table 54. SCL frequency (f_PCLK1= 42 MHz.,V_DD = 3.3 V)⁽¹⁾⁽²⁾
f_SCL (kHz)
I2C_CCR value
R_P = 4.7 kΩ
400
0x8019
300
0x8021
200
0x8032
100
0x0096
50
0x012C
20
0x02EE
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 ±2%. These variations depend on the accuracy of the external
components used to design the application.
SPI interface characteristics
Unless otherwise specified, the parameters given in Table 55 for SPI are derived from tests
performed under the ambient temperature, f_PCLKx frequency and V_DD supply voltage
conditions summarized in Table 14 with the following configuration:
• Output speed is set to OSPEEDRy[1:0] = 10
• Capacitive load C = 30 pF
• Measurement points are done at CMOS levels: 0.5 V_DD
Refer to Section 5.3.16: I/O port characteristics for more details on the input/output alternate
function characteristics (NSS, SCK, MOSI, MISO).
Symbol
Table 55. SPI dynamic characteristics⁽¹⁾
Parameter
Conditions
Min
Typ
Max Unit
f_SCK
SPI clock frequency
1/t_c(SCK)
Duty(SCK)
Duty cycle of SPI clock
frequency
Master mode, SPI1,
2.7V < V_DD < 3.6V
Slave mode, SPI1,
2.7V < V_DD < 3.6V
Master mode, SPI1/2/3,
1.7V < V_DD < 3.6V
Slave mode, SPI1/2/3,
1.7V < V_DD < 3.6V
Slave mode
42
-
-
42
MHz
21
-
-
21
30
50
70
%
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