This repository implements a productive timer using a state machine on STM32 microcontroller, featuring an OLED display and push buttons for user interaction.
- Countdown timer with productivity tracking.
- OLED display output for timer and status messages.
- Four physical buttons for timer control: Increase, Decrease, Start/Pause, Abort.
- Debouncing and button state management for reliable user input.
The display is handled by functions using the SSD1306 controller. It is interacted with via I2C, typically connected to:
- SCL (Clock): Connect to STM32 I2C SCL pin.
- SDA (Data): Connect to STM32 I2C SDA pin.
- VCC/GND: Power the OLED with 3.3V (or 5V) and ground.
The firmware uses the following display functions:
SSD1306_GotoXY(x, y): Set cursor position.SSD1306_Puts(str, font, color): Print text.SSD1306_UpdateScreen(): Refresh display.SSD1306_Clear(): Clear the display.
These are used in utility functions like display_time(), display_message(), and display_clear() for presenting timer values and status info.
There are four distinct buttons connected to the MCU GPIOs with the following purposes (as referenced in main.h):
| Button | Purpose | Code (macro) |
|---|---|---|
| Increase Time | Add 1 minute | BTN_VAL_INC (3) |
| Decrease Time | Subtract 1 min | BTN_VAL_DEC (5) |
| Start/Pause | Start/Pause | BTN_VAL_SP (6) |
| Abort | Cancel timer | BTN_VAL_ABRT(1) |
The buttons are scanned and debounced in the main loop (see process_btn_val()). Button reads trigger corresponding user events which the state machine reacts to.
GPIO pins for each button should be specified in your hardware setup. Typically, each button is connected between a designated STM32 pin and ground, with an optional pull-up resistor (internal/external).
Refer to the assets folder for the complete hardware schematic:
- Power up the hardware and connect the OLED display as per the circuit diagram.
- Operate the timer using the four buttons. The OLED will provide real-time feedback.
- The timer supports increment/decrement, start/pause, abort, and displays productivity stats on completion.
Core/Src/: Main sources for the state machine, button processing, display logic.Core/Inc/: Header files and macro definitions.assets/: Contains circuit diagram and other supporting documents.
For more details on the source code: