Datasheet

Functional overview STM32F302x6 STM32F302x8
14/138 DocID025147 Rev 7
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
• V
SS
, V
DD
=
2.0 to 3.6 V: external power supply for I/Os and the internal regulator. It is
provided externally through V
DD
pins.
• V
SSA
, V
DDA
= 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
V
DDA
differs from one analog peripheral to another. Table 3 provides the summary of
the V
DDA
ranges for analog peripherals. The V
DDA
voltage level must always be greater
than or equal to the V
DD
voltage level and must be provided first.
• V
BAT
= 1.65 to 3.6 V: power supply for RTC, external clock 32 kHz oscillator and
backup registers (through power switch) when V
DD
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,
V
POR/PDR, without the need for an external reset circuit.
• The POR monitors only the V
DD
supply voltage. During the startup phase it is required
that V
DDA
should arrive first and be greater than or equal to V
DD
.
• The PDR monitors both the V
DD
and V
DDA
supply voltages, however the V
DDA
power
supply supervisor can be disabled (by programming a dedicated Option bit) to reduce
the power consumption if the application design ensures that V
DDA
is higher than or
equal to V
DD
.
The device features an embedded programmable voltage detector (PVD) that monitors the
V
DD
power supply and compares it to the VPVD threshold. An interrupt can be generated
when V
DD
drops below the V
PVD
threshold and/or when V
DD
is higher than the V
PVD
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 V
DDA
supply Maximum V
DDA
supply
ADC/COMP 2.0 V 3.6 V
DAC/OPAMP 2.4 V 3.6 V
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