The **STM32L412RBU3P** is a member of the STM32L4 series by STMicroelectronics. It is an ultra-low-power microcontroller based on the high-performance **ARM® Cortex®-M4** 32-bit RISC core, operating at a frequency of up to 80 MHz. --- ### 1. Key Technical Specifications The "RBU3P" suffix indicates specific packaging and temperature ratings. Below is a breakdown of the core electronic specifications: | Feature | Specification | | :--- | :--- | | **Core** | ARM® Cortex®-M4 with FPU (Floating Point Unit) | | **Flash Memory** | 128 KB | | **SRAM** | 40 KB | | **Max Clock Speed** | 80 MHz | | **Operating Voltage** | 1.71V to 3.6V | | **Package** | LQFP64 (64-pin Low-profile Quad Flat Pack) | | **I/O Ports** | 52 GPIOs | --- ### 2. Low-Power Capabilities One of the defining characteristics of this chip is its power management. It utilizes **FlexPowerControl**, which allows independent power supply for different peripherals. * **Shutdown Mode:** 28 nA (with wakeup pins) * **Standby Mode:** 280 nA (with RTC and 40 KB RAM retention) * **Stop 2 Mode:** 1.0 µA (with full RAM retention) * **Run Mode:** 84 µA/MHz --- ### 3. Integrated Peripheral Set The STM32L412RBU3P is highly integrated, reducing the need for external electronic components: #### Analog Peripherals * **ADC:** 1x 12-bit Analog-to-Digital Converter (up to 5 Msps). * **Internal Reference Voltage:** Built-in 2.048V or 2.5V reference. * **Operational Amplifiers:** 1x internal op-amp. * **Comparators:** 2x ultra-low-power comparators. #### Communication Interfaces * **USART/UART:** 3x interfaces (supporting ISO 7816, LIN, IrDA). * **I2C:** 3x interfaces (supporting SMBus/PMBus). * **SPI:** 2x interfaces. * **USB:** 1x USB 2.0 full-speed device controller (crystal-less operation possible). --- ### 4. Part Number Decoder (RBU3P) The suffix provides critical information for electronic procurement and PCB design: | Suffix Segment | Meaning | | :--- | :--- | | **R** | 64 Pins | | **B** | 128 KB Flash Memory | | **U** | Ultra-low-power technology | | **3** | Temperature range: -40°C to +125°C | | **P** | Dedicated Package/Process indicator | --- ### 5. Simple Pinout Example (Power/Clock) When designing the circuit, the following pins are fundamental: ```c // Typical Minimal Hardware Connections Pin 1 -> VLCD (Liquid Crystal Display supply) Pin 12 -> VSS (Ground) Pin 13 -> VDD (Digital Power 1.71V - 3.6V) Pin 32 -> VSS (Ground) Pin 48 -> VDD (Digital Power) Pin 64 -> VSS (Ground) ``` ---