How to use STM32 microchip as a standalone project like mega2560 or atmega328 microchip?

[RTrip.1]

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[Piranha]

Design the board, by the parts, solder the parts - how does STM32 differ from any other chip?

[berendi]

There are Getting started with ... series hardware development application notes for each MCU series.

A minimal design should have

• Power and ground to ALL Vdd*/Vss* pins.
• Decoupling capacitors on all supply pins.
• Pulldown on the BOOT0 pin if there is one.
• Maybe a few additional passive components on higher end MCUs.
• A way to upload the firmware: via ST-Link (connect SWDIO, SWCLK, Vdd, GND), or via the internal bootloader (see AN2606).

Analog applications using ADC/DAC/COMP etc should have a separate Vdda/Vssa supply, otherwise they can be connected to Vdd/Vss.

[RTrip.1]

Does the factory shipped chip (STM32 series) contain a hardcoded bootloader that allows them to be programmed via USART1 ?

[berendi]

Check AN2606 STM32 microcontroller system memory boot mode for your part number. Some of them do, some might not, some have it on another UART port. Watch out for the activation pattern.