• Datasheets
  • DS14581 STM32U031x4/6/8
  • DS14548 STM32U073x8/B/C
  • DS14463 STM32U083xC
• Application Notes
  • AN5938 Getting started with STM32U0 MCUs hardware development
  • AN2606 STM32 microcontroller system memory boot mode
• Reference Manual
  • RM0503 Reference manual

1. Nucleo-U083RC (STM32U083RCT6)
   • Purchasing
     • S$21.68 at element14
   • User Manuals
     • UM1727 Getting started with STM32 Nucleo board software development tools
     • UM3256 STM32 Nucleo-64 boards (MB1932)
2. STM32U083C-DK (STM32U083MC)
   • Purchasing
     • S$37.06 at element14
   • User Manuals
     • UM3292 Discovery kit with STM32U083MC MCU
     • UM3313 STM32CubeU0 STM32U083C-DK demonstration firmware

• VDDx
  • 1.71 ≤ VDDx ≤ 3.60 V (absolute maximum: 4.00 V)
  • Nucleo-083RC LEDs become very dim when 3.3V net falls below 1.80 V
• Brownout Reset¹⁾
  • Selectable: 1.7, 2.0, 2.2, 2.5 or 2.8 V

In order to use the native USB for programming on pins PA11 and PA12, the following settings must be done in STM32CubeProgrammer → Option bytes → User Configuration.

Option byte name	Value	Description	Notes
NBOOT_SEL	0 (Unchecked)	BOOT0 pin (legacy mode)	Factory setting is 1. You must change it to 0 to keep USB DFU programming capability.
nBOOT1	1 (Checked)	Boot from Flash if BOOT0 = 1, otherwise System Memory	This is the factory setting
NRST_MODE	1 or 3	1: Reset input only 3. Bidirectional reset: The NRST pin is configured in reset input/output (legacy) mode	3 is the factory setting

Note: Native USB does not enumerate if HCLK is lower than the default 16 MHz, e.g. by adjusting the AHB prescaler.

State	Peripherals	Memory	Voltage Supplies (VDDx)	STM32RTC::LSI_CLOCK	STM32RTC::LSE_CLOCK	STM32RTC::HSE_CLOCK
LowPower.idle()	On	On	On	Supported	Supported	Supported
LowPower.sleep()	On	On	On	Supported	Supported	Supported
LowPower.deepSleep()	On	On	On	Supported	Supported	Supported
LowPower.shutdown()	Off	Off	Off		Supported

: External hardware required

• External 32.768 kHz crystal for LSE²⁾

• rtc.setClockSource(STM32RTC::LSE_CLOCK);
  rtc.begin();

1. Hardware
   1. Choose a crystal oscillator³⁾
   2. Choose the load capacitance
      • C1 = C2 = 2 * (C_L - C_stray)
      • “Stray capacitance C_stray comes from the pins of the chip and parasitics from the board. It is often approximated as 5pF.”⁴⁾
2. Software
   1. Configure LSE drive level: __HAL_RCC_LSEDRIVE_CONFIG(__LSEDRV__); Select the lowest value that can provide robust LSE start-up⁵⁾
      Substitute __LSEDRV__ substitute with:
      1. RCC_LSEDRIVE_LOW
      2. RCC_LSEDRIVE_MEDIUMLOW (default if __HAL_RCC_LSEDRIVE_CONFIG is not called)
      3. RCC_LSEDRIVE_MEDIUMHIGH
      4. RCC_LSEDRIVE_HIGH