# STM32L052 Development board

Quick and compact STM32L052 development board

I usually use Arduino as the default choice for all my projects thanks to all libraries available, in specifics cases, I switch to STM32 to get power computing power or peripherals the ATMega328 is not able to provide. More and more projects need ST’s micro-controllers so it is time to switch to more modern µC: I recently designed a new all-around board based on STM32L0, but all STM32 with the same package should work.

Board picture

# Requirements

• Breakout all I/Os
• WS2812 RGB led: blinky things, you know!
• 3.3V LDO regulator
• Easy way to select Vin or Vusb (jumper)
• Easy way to select BOOT0 (jumper)
• USB connector and ESD protection
• 200 to 300 mA mosfet to control more power or other voltages
• Reset button
• “FDTI” pinout connector for serial communications, and to try ST serial bootloader
• All components on one side, so the board can be easily reflowed with hotplate

# Caveats & improvements

The batch of WS2812b I have works well @3.3V, but it might not be the case for all LEDs as the datasheet specifies Vin=[3.5;5V]. Also, old habits die hard, I tried to put too many things on a small board, so routing can be improved, and for the next revision I will change :

• As ST-Link is always used to program the board, BOOT0 can be tied to the ground or only be a solder bridge.
• I will not switch from Vin to Vusb really often, so this jumper can be converted to a solder bridge too.