STM32F051K6U6 datasheet(21/40 Pages) STMICROELECTRONICS

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STM32F051x

Functional overview

Doc ID 018746 Rev 2

21/22

3.19

Analog to digital converter (ADC)

The 12-bit analog to digital converter has up to 16 external and 3 internal (temperature

sensor, voltage reference, VBAT voltage measurement) channels and performs conversions

in single-shot or scan modes. In scan mode, automatic conversion is performed on a

selected group of analog inputs.

The ADC can be served by the DMA controller.

An analog watchdog feature allows very precise monitoring of the converted voltage of one,

some or all selected channels. An interrupt is generated when the converted voltage is

outside the programmed thresholds.

3.19.1

Temperature sensor

The temperature sensor generates a voltage that varies linearly with temperature. The

conversion range is between 2 V < VDDA < 3.6 V. The temperature sensor is internally

connected to the ADC_IN16 input channel which is used to convert the sensor output

voltage into a digital value.

As the offset of the temperature sensor varies from chip to chip due to process variation, the

internal temperature sensor is mainly suitable for applications that detect temperature

changes instead of absolute temperatures. If an accurate temperature reading is needed,

then an external temperature sensor part should be used.

3.19.2

VBAT battery voltage monitoring

This embedded hardware feature allows the application to measure the VBAT battery voltage

using the internal ADC channel ADC_IN18. As the VBAT voltage may be higher than VDDA,

and thus outside the ADC input range, the VBAT pin is internally connected to a bridge

divider by 2. As a consequence, the converted digital value is half the VBAT voltage.

Table 9.

No. of capacitive sensing channels available on STM32F051xx devices

Analog I/O group

Number of capacitive sensing channels

STM32F051Rx

STM32F051Cx

STM32F051Kx

Number of capacitive

sensing channels

STM32F051K6U6 Datasheet(PDF) 21 Page - STMicroelectronics