STM32F042F6 datasheet(56/117 Pages) STMICROELECTRONICS

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Electrical characteristics

STM32F042x4 STM32F042x6

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trigger circuits used to discriminate the input value. Unless this specific configuration is

required by the application, this supply current consumption can be avoided by configuring

these I/Os in analog mode. This is notably the case of ADC input pins which should be

configured as analog inputs.

Caution:

Any floating input pin can also settle to an intermediate voltage level or switch inadvertently,

as a result of external electromagnetic noise. To avoid current consumption related to

floating pins, they must either be configured in analog mode, or forced internally to a definite

digital value. This can be done either by using pull-up/down resistors or by configuring the

pins in output mode.

I/O dynamic current consumption

In addition to the internal peripheral current consumption measured previously (see

Table 32: Peripheral current consumption

), the I/Os used by an application also contribute

to the current consumption. When an I/O pin switches, it uses the current from the I/O

supply voltage to supply the I/O pin circuitry and to charge/discharge the capacitive load

(internal or external) connected to the pin:

where

ISW is the current sunk by a switching I/O to charge/discharge the capacitive load

VDDIOx is the I/O supply voltage

fSW is the I/O switching frequency

C is the total capacitance seen by the I/O pin: C = CINT + CEXT + CS

CS is the PCB board capacitance including the pad pin.

The test pin is configured in push-pull output mode and is toggled by software at a fixed

frequency.

ISW

VDDIOx fSW C

STM32F042F6 데이터시트(PDF) 56 Page - STMicroelectronics