STM32F302X8 datasheet(13/139 Pages) STMICROELECTRONICS

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DS9896 Rev 8

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STM32F302x6 STM32F302x8

Functional overview

3.4

Cyclic redundancy check calculation unit (CRC)

The CRC (cyclic redundancy check) calculation unit is used to get a CRC code using a

configurable generator polynomial value and size.

Among other applications, CRC-based techniques are used to verify data transmission or

storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of

verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of

the software during runtime, to be compared with a reference signature generated at

linktime and stored at a given memory location.

3.5

Power management

3.5.1

Power supply schemes

•

VSS, VDD = 2.0 to 3.6 V: external power supply for I/Os and the internal regulator. It is

provided externally through VDD pins.

•

VSSA, VDDA = 2.0 to 3.6 V: external analog power supply for ADC, DAC, comparators,

operational amplifier, reset blocks, RCs and PLL. The minimum voltage to be applied to

VDDA differs from one analog peripheral to another. Table 3 provides the summary of

the VDDA ranges for analog peripherals. The VDDA voltage level must always be greater

than or equal to the VDD voltage level and must be provided first.

•

VBAT = 1.65 to 3.6 V: power supply for RTC, external clock 32 kHz oscillator and

backup registers (through power switch) when VDD is not present.

3.5.2

Power supply supervisor

The device has an integrated power-on reset (POR) and power-down reset (PDR) circuits.

They are always active, and ensure proper operation above a threshold of 2 V. The device

remains in reset mode when the monitored supply voltage is below a specified threshold,

VPOR/PDR, without the need for an external reset circuit.

•

The POR monitors only the VDD supply voltage. During the startup phase it is required

that VDDA should arrive first and be greater than or equal to VDD.

•

The PDR monitors both the VDD and VDDA supply voltages, however the VDDA power

supply supervisor can be disabled (by programming a dedicated Option bit) to reduce

the power consumption if the application design ensures that VDDA is higher than or

equal to VDD.

The device features an embedded programmable voltage detector (PVD) that monitors the

VDD power supply and compares it to the VPVD threshold. An interrupt can be generated

when VDD drops below the VPVD threshold and/or when VDD is higher than the VPVD

threshold. The interrupt service routine can then generate a warning message and/or put

the MCU into a safe state. The PVD is enabled by software.

Table 3. External analog supply values for analog peripherals

Analog peripheral

Minimum VDDA supply

Maximum VDDA supply

ADC/COMP

2.0 V

3.6 V

DAC/OPAMP

2.4 V

3.6 V

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