Coffee Machine Controller

An embedded firmware solution for an automated coffee machine running on the Freescale FRDM-KL25Z development board and the EDU-mod mixing unit. Features non-blocking cooperative multitasking, analog potentiometer configuration, an interactive LCD wizard, and fail-safe drainage mechanisms.

Features

Beverage Programs

• Espresso — single-shot coffee extraction with customizable coffee strength
• Lungo — extended brew diluted with hot water from reservoir
• Doppio — double-cycle extraction sequence for rich coffee output

Hardware Control

• Direct register-level GPIO control for 5 solenoid valves (SV1–SV5) and stirrer motor
• Continuous level monitoring across 8 discrete sensors (H1–H8)
• Non-blocking cooperative multitasking driven by a 1 ms SysTick timer
• Software debouncing for push-button inputs with edge detection
• ADC potentiometer sampling with hardware averaging for smooth adjustments

User Interface & Safety

• 4x20 character LCD interface with dynamic graphical progress bars
• Interactive setup wizard for coffee strength and sugar level adjustment
• Real-time status screens indicating current preparation phases and timers
• Emergency cancel (STORNO) with automated, safe tank and mixer evacuation

Hardware Architecture

• MCU Board — Freescale / NXP FRDM-KL25Z (ARM Cortex-M0+ @ 48 MHz)
• Mixing Unit — EDU-mod fixture with 3 supply tanks (Coffee, Water, Sugar) and 1 mixing chamber
• Actuators — 5 solenoid valves (SV1–SV5) and 1 DC mixer motor
• Sensors — 8 discrete liquid level sensors (H1–H8) distributed across reservoirs
• Peripherals — 4 push buttons (SW1–SW4), rotary potentiometer (ADC0), and 4x20 character LCD

Tech Stack

• C (C99) bare-metal firmware
• ARM Cortex-M0+ (MKL25Z128VLK4)
• Direct Register Access (zero-overhead hardware control without heavy HALs)
• Kinetis Design Studio (KDS) & GNU ARM Toolchain
• No external dependencies

Requirements

• Freescale / NXP FRDM-KL25Z development board
• EDU-mod Mísicí jednotka (Mixing Unit) fixture
• Kinetis Design Studio (KDS) v3.x or compatible GCC ARM Embedded toolchain
• OpenSDA debug driver (P&E Micro or CMSIS-DAP)

How to Run

1. Clone the repository
2. Open Kinetis Design Studio and import the project into your workspace
3. Connect the FRDM-KL25Z board and EDU-mod fixture via USB OpenSDA
4. Build the project using the GCC ARM toolchain
5. Flash and run the firmware onto the target MCU

Structure

CoffeMachine/
├── Includes/                           # CMSIS core and MKL25Z MCU register definitions
│   ├── MKL25Z4.h                       # Device-specific register mappings
│   └── core_cm0plus.h                  # Cortex-M0+ core definitions
├── Project_Settings/                   # Linker scripts, debugger config, startup code
│   ├── Debugger/                       # GDB and OpenSDA launch configurations
│   ├── Linker_Files/                   # Flash and RAM memory layout scripts
│   └── Startup_Code/                   # MCU startup and interrupt vector table
├── Sources/                            # Application and peripheral driver source files
│   ├── drv_adc.c / .h                  # Potentiometer ADC0 driver and value scaling
│   ├── drv_gpio.c / .h                 # GPIO configuration and button debounce logic
│   ├── drv_kava.c / .h                 # EDU-mod driver (valves SV1–SV5, mixer, sensors H1–H8)
│   ├── drv_lcd.c / .h                  # 4x20 character LCD driver and progress bar rendering
│   ├── drv_systick.c / .h              # 1 ms SysTick timer for non-blocking scheduling
│   └── main.c                          # System initialization and cooperative run loop
├── zadani/                             # Project assignment documentation and schematics
├── plan.md                             # Issue tracking roadmap and task breakdown
└── README.md