Datasheet

DocID028087 Rev 4 41/193
STM32F412xE/G Functional overview
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3.33 Random number generator (RNG)
All devices embed an RNG that delivers 32-bit random numbers generated by an integrated
analog circuit.
3.34 General-purpose input/outputs (GPIOs)
Each of the GPIO pins can be configured by software as output (push-pull or open-drain,
with or without pull-up or pull-down), as input (floating, with or without pull-up or pull-down)
or as peripheral alternate function. Most of the GPIO pins are shared with digital or analog
alternate functions. All GPIOs are high-current-capable and have speed selection to better
manage internal noise, power consumption and electromagnetic emission.
The I/O configuration can be locked if needed by following a specific sequence in order to
avoid spurious writing to the I/Os registers.
Fast I/O handling allowing maximum I/O toggling up to 100 MHz.
3.35 Analog-to-digital converter (ADC)
One 12-bit analog-to-digital converter is embedded and shares up to 16 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.
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.
To synchronize A/D conversion and timers, the ADCs could be triggered by any of TIM1,
TIM2, TIM3, TIM4 or TIM5 timer.
3.36 Temperature sensor
The temperature sensor has to generate a voltage that varies linearly with temperature. The
conversion range is between 1.7 V and 3.6 V. The temperature sensor is internally
connected to the ADC_IN18 input channel which is used to convert the sensor output
voltage into a digital value. Refer to the reference manual for additional information.
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.
3.37 Serial wire JTAG debug port (SWJ-DP)
The ARM SWJ-DP interface is embedded, and is a combined JTAG and serial wire debug
port that enables either a serial wire debug or a JTAG probe to be connected to the target.
Debug is performed using 2 pins only instead of 5 required by the JTAG (JTAG pins could
be re-use as GPIO with alternate function): the JTAG TMS and TCK pins are shared with
SWDIO and SWCLK, respectively, and a specific sequence on the TMS pin is used to
switch between JTAG-DP and SW-DP.
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