STM32H7B3AI datasheet(22/238 Pages) STMICROELECTRONICS

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3.18

Analog-to-digital converters (ADCs)

The STM32H7B3xI devices embed two analog-to-digital converters, whose resolution can be configured to 16,

14, 12, 10 or 8 bits. Each ADC shares up to 24 external channels, performing conversions in the single-shot or

scan mode. In scan mode, automatic conversion is performed on a selected group of analog inputs.

Additional logic functions embedded in the ADC interface allow:

•

Simultaneous sample and hold

•

Interleaved sample and hold

The ADC can be served by the DMA controller, thus allowing to automatically transfer ADC converted values to a

destination location without any software action.

In addition, an analog watchdog feature can accurately monitor the converted voltage of one, some or all selected

channels. An interrupt is generated when the converted voltage is outside the programmed thresholds.

To synchronize A/D conversion and timers, the ADCs could be triggered by any of TIM1, TIM2, TIM3, TIM4, TIM6,

TIM8, TIM15, and LPTIM1 timers.

3.19

Analog temperature sensor

The STM32H7B3xI embeds an analog temperature sensor that generates a voltage (VTS) that varies linearly

with the temperature. This temperature sensor is internally connected to ADC2_IN18. The conversion range is

between 1.7 V and 3.6 V. It can measure the device junction temperature ranging from −40 to +125 °C.

The temperature sensor have a good linearity, but it has to be calibrated to obtain a good overall accuracy of the

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

the uncalibrated internal temperature sensor is suitable for applications that detect temperature changes only.

To improve the accuracy of the temperature sensor measurement, each device is individually factory-calibrated

by ST. The temperature sensor factory calibration data are stored by ST in the System memory area, which is

accessible in read-only mode.

3.20

Digital temperature sensor (DTS)

The STM32H7B3xI embeds a sensor that converts the temperature into a square wave which frequency

is proportional to the temperature. The PCLK or the LSE clock can be used as reference clock for the

measurements. A formula given in the product reference manual (RM0455) allows to calculate the temperature

according to the measured frequency stored in the DTS_DR register.

3.21

VBAT operation

The VBAT power domain contains the RTC, the backup registers and the backup SRAM.

To optimize battery duration, this power domain is supplied by VDD when available or by the voltage applied on

VBAT pin (when VDD supply is not present). VBAT power is switched when the PDR detects that VDD dropped

below the PDR level.

The voltage on the VBAT pin could be provided by an external battery, a supercapacitor or directly by VDD, in

which case, the VDD mode is not functional.

VBAT operation is activated when VDD is not present.

The VBAT pin supplies the RTC, the backup registers and the backup SRAM.

The devices embed an internal VBAT battery charging circuitry that can be activated when VDD is present.

Note:

When the microcontroller is supplied from VBAT, external interrupts and RTC alarm/events do not exit it from

VBAT operation.

When PDR_ON pin is connected to VSS (Internal Reset OFF), the VBAT functionality is no more available and

VBAT pin should be connected to VDD.

3.22

Digital-to-analog converters (DAC)

The devices features one dual-channel DAC (DAC1), located in the CD domain, plus one single-channel DAC

(DAC2), located in the SRD domain.

The three 12-bit buffered DAC channels can be used to convert three digital signals into three analog voltage

signal outputs.

The following feature are supported:

STM32H7B3xI

Analog-to-digital converters (ADCs)

DS13139 - Rev 8

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