STM32F401XD datasheet(19/135 Pages) STMICROELECTRONICS

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STM32F401xD STM32F401xE

Functional overview

3.12

Boot modes

At startup, boot pins are used to select one out of three boot options:

•

Boot from user Flash

•

Boot from system memory

•

Boot from embedded SRAM

The boot loader is located in system memory. It is used to reprogram the Flash memory by

using either USART1(PA9/10), USART2(PD5/6), USB OTG FS in device mode (PA11/12)

through DFU (device firmware upgrade), I2C1(PB6/7), I2C2(PB10/3), I2C3(PA8/PB4),

SPI1(PA4/5/6/7), SPI2(PB12/13/14/15) or SPI3(PA15, PC10/11/12).

For more detailed information on the bootloader, refer to Application Note: AN2606,

STM32™ microcontroller system memory boot mode.

3.13

Power supply schemes

•

VDD = 1.7 to 3.6 V: external power supply for I/Os with the internal supervisor

(POR/PDR) disabled, provided externally through VDD pins. Requires the use of an

external power supply supervisor connected to the VDD and PDR_ON pins.

•

VDD = 1.8 to 3.6 V: external power supply for I/Os and the internal regulator (when

enabled), provided externally through VDD pins.

•

VSSA, VDDA = 1.7 to 3.6 V: external analog power supplies for ADC, Reset blocks, RCs

and PLL. VDDA and VSSA must be connected to VDD and VSS, respectively, with

decoupling technique.

•

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.

Refer to Figure 18: Power supply scheme for more details.

STM32F401XD Datasheet(PDF) 19 Page - STMicroelectronics