Clock i2c l0

STM32 Binary Clock Lab

This repository is a development sandbox for a binary clock built around different STM32 microcontrollers and peripheral combinations. It contains the current clock firmware, earlier hardware ports, reusable device drivers, board experiments, KiCad sources, and end-user documentation.

The project is intentionally broader than a single finished product: it is used to test display concepts, sensors, RTC implementations, power management, alarm behavior, and small-memory firmware optimizations on real hardware.

MCU variants

• STM32L010F4P6 - current primary target and the most complete low-power build.
• STM32F030F4P6 - compact CubeMX/HAL port used during early hardware tests.
• STM32F407G-DISC1 - original prototype and development platform.

The default CMake configuration currently builds the STM32L010F4P6 firmware. Board-specific notes and wiring are kept under Core/Src/boards.

Hardware and drivers

The repository includes implementations or experiments for:

• a 16-LED binary display driven by chained 74HC595 shift registers;
• a 128x32 OLED display;
• an internal STM32 RTC clocked from a 32.768 kHz LSE crystal;
• the external DS1302 RTC used by earlier board versions;
• AHT10 and DHT11 temperature/humidity sensors;
• BH1750 and analog LDR light sensing with automatic display brightness;
• an ADC resistor ladder for five control buttons;
• active-buzzer alarm output and three persistent alarm slots;
• PIR motion detection, idle display shutdown, battery measurement, and standby power handling.

Separate branches also preserve display and peripheral experiments such as the MAX721x 8x8 LED matrix version.

Firmware layout

• Core/Src/app - clock behavior, alarms, display rendering, environment data, automatic modes, and user-interface state.
• Core/Src/boards - MCU/board-specific GPIO and peripheral implementations.
• Core/Src/drivers - reusable drivers for buttons, buzzer, DHT11, DS1302, light sensing, and shift registers.
• Drivers - STM32 CMSIS and HAL sources.
• docs - user guide, technical reference, diagrams, and promotional assets.
• Clocl i2C l0 16 -2 595 - KiCad schematic and PCB sources for the current STM32L010-based hardware.

Build

The current target requires CMake, Ninja, and the GNU Arm Embedded toolchain.

cmake --preset Release
cmake --build --preset Release

Debug and Release presets place their output under build/.

Documentation

• User manual
• Technical reference
• STM32L010 board notes
• STM32F030 board notes
• STM32F407 board notes

This is an experimental hardware/firmware repository. Verify the selected board configuration, supply voltage, pin mapping, and programming setup before using it on assembled hardware.