Coffee Maker Firmware

The official bare-metal firmware for IoT coffee makers with ARM Cortex-M4 microcontrollers.

Installation

Prerequisites

# macOS
brew install arm-none-eabi-gcc

# Ubuntu/Debian
sudo apt-get install gcc-arm-none-eabi

# Arch Linux
sudo pacman -S arm-none-eabi-gcc

Build

git clone https://github.com/harpertoken/brew.git
cd brew
make clean && make

Docker

# Pull from GitHub Container Registry
docker pull ghcr.io/harpertoken/brew:latest

# Pull from Docker Hub
docker pull harpertoken/brew:latest

# Run the coffee maker dashboard
docker run -p 8080:8080 ghcr.io/harpertoken/brew:latest

Usage

Basic Example

#include "heater.h"
#include "pump.h"
#include "control.h"

int main(void) {
    heater_init();
    pump_init();

    while(1) {
        coffee_state_machine();
    }

    return 0;
}

Advanced Configuration

// Temperature control
#define MAX_TEMP_CELSIUS    95
#define MIN_TEMP_CELSIUS    20
#define TEMP_HYSTERESIS     5

// Water level protection
#define MIN_WATER_LEVEL     50   // ml
#define CRITICAL_WATER      10   // ml

// Safety timing
#define MAX_BREW_TIME_MS    300000  // 5 minutes

Hardware Setup

// Pin configuration in board/board.h
#define HEATER_PIN        12
#define PUMP_PIN          13
#define TEMP_SENSOR_PIN   0
#define WATER_SENSOR_PIN  1

API Reference

Core Functions

heater_init()

Initialize heater control system.

heater_on() / heater_off()

Control heater state with safety checks.

pump_init()

Initialize pump control system.

pump_on() / pump_off()

Control pump state with flow monitoring.

coffee_state_machine()

Main brewing logic with safety interlocks.

State Management

typedef enum {
    IDLE,
    HEATING,
    BREWING,
    DONE
} coffee_state_t;

Memory Layout

• Flash: 256KB (STM32F4)
• RAM: 64KB total
• Stack: 4KB (configurable)
• Bootloader: 32KB reserved

Examples

IoT Integration

# Start web dashboard
go run examples/web_dashboard.go

# Connect to AWS IoT
go run examples/iot_controller.go

# Monitor metrics
go run examples/metrics_collector.go

Cloud Deployment

# Deploy infrastructure
aws cloudformation deploy --template-file cloud/infrastructure.yaml --stack-name coffee-maker

# Run monitoring stack
docker-compose up -d

Development

Quality Assurance

make quality         # Run all quality checks
make inspect         # Analyze memory layout
make size           # Memory usage report

Testing

make flash          # Flash to hardware
make debug          # Start GDB session

Pre-commit Hooks

pre-commit install  # Install quality gates

Configuration

Memory Limits

Configure in linker.ld:

MEMORY
{
    FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 256K
    RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 64K
}

Build Options

# Debug build
make CFLAGS="-mcpu=cortex-m4 -mthumb -g3 -DDEBUG"

# Release build
make CFLAGS="-mcpu=cortex-m4 -mthumb -O2 -DNDEBUG"

Safety & Security

This firmware implements production-grade safety practices:

• Memory safety: No dynamic allocation, bounds checking
• Static analysis: cppcheck, MISRA C compliance
• Stack protection: Overflow detection and limits
• Fail-safe design: Safe defaults on all error conditions

Critical Constraints

⚠️ No dynamic memory allocation - Uses static allocation only ⚠️ No standard library - Bare metal implementation ⚠️ Real-time constraints - Interrupt-driven architecture

Contributing

We welcome contributions! Please see our contributing guidelines.

Development Setup

./setup_dev.sh      # Install dependencies
pre-commit install  # Setup quality gates

Code Standards

• Follow MISRA C:2012 guidelines
• All code must pass static analysis
• Hardware changes require testing
• Documentation updates required

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

• Documentation: docs/
• Issues: GitHub Issues
• Discussions: GitHub Discussions

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Copyright (c) 2026 harpertoken