Embedded Systems with TuskLang and Rust

🔧 Embedded Foundation

Embedded systems development with TuskLang and Rust provides memory safety, zero-cost abstractions, and direct hardware control. This guide covers bare metal programming, real-time systems, and hardware interface development.

🏗️ Embedded Architecture

System Architecture

[embedded_architecture]
bare_metal: true
no_std: true
real_time: true
hardware_abstraction: true
[embedded_components]
microcontroller: "target_hardware"
peripherals: "gpio_uart_spi_i2c"
memory: "flash_ram"
interrupts: "real_time_events"

Target Configuration

[target_configuration]
target_triple: "thumbv7m-none-eabi"
linker_script: "memory.x"
panic_handler: "custom_panic"
allocator: "custom_allocator"

🔧 Bare Metal Programming

No-Std Environment

[no_std_environment]
core_library: true
custom_panic: true
custom_allocator: true
[no_std_implementation]
#![no_std]
#![no_main]
use core::panic::PanicInfo;
use core::alloc::{GlobalAlloc, Layout};
// Custom panic handler
#[panic_handler]
fn panic(_info: &PanicInfo) -> ! {
    loop {
        // Halt the processor
        cortex_m::asm::bkpt();
    }
}
// Custom allocator for embedded systems
pub struct EmbeddedAllocator;
unsafe impl GlobalAlloc for EmbeddedAllocator {
    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
        // Simple bump allocator
        static mut HEAP: [u8; 1024] = [0; 1024];
        static mut NEXT: usize = 0;
        
        let start = NEXT;
        let end = start + layout.size();
        
        if end <= HEAP.len() {
            NEXT = end;
            HEAP.as_mut_ptr().add(start)
        } else {
            core::ptr::null_mut()
        }
    }
    
    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
        // Simple allocator doesn't deallocate
    }
}
#[global_allocator]
static ALLOCATOR: EmbeddedAllocator = EmbeddedAllocator;
// Entry point
#[no_mangle]
pub extern "C" fn _start() -> ! {
    // Initialize hardware
    init_hardware();
    
    // Main application loop
    loop {
        // Application logic
        process_events();
        
        // Sleep to save power
        cortex_m::asm::wfi();
    }
}
fn init_hardware() {
    // Initialize GPIO, UART, etc.
}
fn process_events() {
    // Process system events
}

Memory Management

[memory_management]
static_allocation: true
stack_management: true
heap_limitations: true
[memory_implementation]
// Static memory allocation
static mut BUFFER: [u8; 1024] = [0; 1024];
static mut COUNTER: u32 = 0;
// Stack-based data structures
pub struct StackBuffer<T, const N: usize> {
    data: [T; N],
    len: usize,
}
impl<T: Default + Copy, const N: usize> StackBuffer<T, N> {
    pub fn new() -> Self {
        Self {
            data: [T::default(); N],
            len: 0,
        }
    }
    
    pub fn push(&mut self, item: T) -> Result<(), &'static str> {
        if self.len < N {
            self.data[self.len] = item;
            self.len += 1;
            Ok(())
        } else {
            Err("Buffer full")
        }
    }
    
    pub fn pop(&mut self) -> Option<T> {
        if self.len > 0 {
            self.len -= 1;
            Some(self.data[self.len])
        } else {
            None
        }
    }
    
    pub fn len(&self) -> usize {
        self.len
    }
    
    pub fn is_empty(&self) -> bool {
        self.len == 0
    }
}
// Memory pool for dynamic allocation
pub struct MemoryPool<const N: usize> {
    memory: [u8; N],
    used: [bool; N],
}
impl<const N: usize> MemoryPool<N> {
    pub fn new() -> Self {
        Self {
            memory: [0; N],
            used: [false; N],
        }
    }
    
    pub fn allocate(&mut self, size: usize) -> Option<&mut [u8]> {
        if size == 0 || size > N {
            return None;
        }
        
        for i in 0..=N - size {
            if !self.used[i..i + size].iter().any(|&used| used) {
                for j in i..i + size {
                    self.used[j] = true;
                }
                return Some(&mut self.memory[i..i + size]);
            }
        }
        
        None
    }
    
    pub fn deallocate(&mut self, slice: &mut [u8]) {
        let start = slice.as_ptr() as usize - self.memory.as_ptr() as usize;
        let end = start + slice.len();
        
        for i in start..end {
            if i < N {
                self.used[i] = false;
            }
        }
    }
}

🔌 Hardware Interfaces

GPIO Control

[gpio_control]
pin_modes: true
digital_io: true
interrupt_handling: true
[gpio_implementation]
// GPIO pin abstraction
pub struct Pin {
    port: u8,
    pin: u8,
    mode: PinMode,
}
#[derive(Clone, Copy)]
pub enum PinMode {
    Input,
    Output,
    InputPullUp,
    InputPullDown,
    Analog,
}
impl Pin {
    pub fn new(port: u8, pin: u8, mode: PinMode) -> Self {
        let mut pin = Self { port, pin, mode };
        pin.configure();
        pin
    }
    
    fn configure(&mut self) {
        // Configure pin mode based on hardware
        match self.mode {
            PinMode::Input => self.set_as_input(),
            PinMode::Output => self.set_as_output(),
            PinMode::InputPullUp => self.set_as_input_pullup(),
            PinMode::InputPullDown => self.set_as_input_pulldown(),
            PinMode::Analog => self.set_as_analog(),
        }
    }
    
    pub fn set_high(&self) {
        if matches!(self.mode, PinMode::Output) {
            // Set pin high
            unsafe {
                // Hardware-specific implementation
                self.write_pin(true);
            }
        }
    }
    
    pub fn set_low(&self) {
        if matches!(self.mode, PinMode::Output) {
            // Set pin low
            unsafe {
                // Hardware-specific implementation
                self.write_pin(false);
            }
        }
    }
    
    pub fn read(&self) -> bool {
        unsafe {
            // Hardware-specific implementation
            self.read_pin()
        }
    }
    
    pub fn toggle(&mut self) {
        if self.read() {
            self.set_low();
        } else {
            self.set_high();
        }
    }
    
    // Hardware-specific methods (to be implemented for target)
    unsafe fn write_pin(&self, _value: bool) {
        // Implementation depends on target hardware
    }
    
    unsafe fn read_pin(&self) -> bool {
        // Implementation depends on target hardware
        false
    }
    
    fn set_as_input(&self) {
        // Implementation depends on target hardware
    }
    
    fn set_as_output(&self) {
        // Implementation depends on target hardware
    }
    
    fn set_as_input_pullup(&self) {
        // Implementation depends on target hardware
    }
    
    fn set_as_input_pulldown(&self) {
        // Implementation depends on target hardware
    }
    
    fn set_as_analog(&self) {
        // Implementation depends on target hardware
    }
}
// GPIO interrupt handling
pub struct GpioInterrupt {
    pin: Pin,
    callback: Option<fn()>,
}
impl GpioInterrupt {
    pub fn new(pin: Pin) -> Self {
        Self {
            pin,
            callback: None,
        }
    }
    
    pub fn set_callback(&mut self, callback: fn()) {
        self.callback = Some(callback);
    }
    
    pub fn enable(&self) {
        // Enable interrupt for the pin
        unsafe {
            // Hardware-specific implementation
            self.enable_interrupt();
        }
    }
    
    pub fn disable(&self) {
        // Disable interrupt for the pin
        unsafe {
            // Hardware-specific implementation
            self.disable_interrupt();
        }
    }
    
    // Hardware-specific methods
    unsafe fn enable_interrupt(&self) {
        // Implementation depends on target hardware
    }
    
    unsafe fn disable_interrupt(&self) {
        // Implementation depends on target hardware
    }
}

UART Communication

[uart_communication]
serial_protocol: true
baud_rate: true
interrupt_driven: true
[uart_implementation]
// UART configuration
pub struct UartConfig {
    baud_rate: u32,
    data_bits: DataBits,
    parity: Parity,
    stop_bits: StopBits,
}
#[derive(Clone, Copy)]
pub enum DataBits {
    Bits8,
    Bits9,
}
#[derive(Clone, Copy)]
pub enum Parity {
    None,
    Even,
    Odd,
}
#[derive(Clone, Copy)]
pub enum StopBits {
    Bits1,
    Bits2,
}
// UART peripheral
pub struct Uart {
    config: UartConfig,
    tx_buffer: StackBuffer<u8, 256>,
    rx_buffer: StackBuffer<u8, 256>,
}
impl Uart {
    pub fn new(config: UartConfig) -> Self {
        let mut uart = Self {
            config,
            tx_buffer: StackBuffer::new(),
            rx_buffer: StackBuffer::new(),
        };
        uart.configure();
        uart
    }
    
    fn configure(&mut self) {
        // Configure UART hardware
        unsafe {
            // Hardware-specific implementation
            self.set_baud_rate(self.config.baud_rate);
            self.set_data_bits(self.config.data_bits);
            self.set_parity(self.config.parity);
            self.set_stop_bits(self.config.stop_bits);
        }
    }
    
    pub fn write(&mut self, data: &[u8]) -> Result<usize, &'static str> {
        let mut written = 0;
        
        for &byte in data {
            if self.tx_buffer.push(byte).is_ok() {
                written += 1;
            } else {
                break;
            }
        }
        
        // Start transmission if not already running
        if written > 0 {
            self.start_transmission();
        }
        
        Ok(written)
    }
    
    pub fn read(&mut self, buffer: &mut [u8]) -> usize {
        let mut read = 0;
        
        for byte in buffer.iter_mut() {
            if let Some(data) = self.rx_buffer.pop() {
                *byte = data;
                read += 1;
            } else {
                break;
            }
        }
        
        read
    }
    
    pub fn write_byte(&mut self, byte: u8) -> Result<(), &'static str> {
        if self.tx_buffer.push(byte).is_ok() {
            self.start_transmission();
            Ok(())
        } else {
            Err("TX buffer full")
        }
    }
    
    pub fn read_byte(&mut self) -> Option<u8> {
        self.rx_buffer.pop()
    }
    
    pub fn is_tx_ready(&self) -> bool {
        // Check if UART is ready to transmit
        unsafe {
            // Hardware-specific implementation
            self.tx_ready()
        }
    }
    
    pub fn is_rx_ready(&self) -> bool {
        // Check if UART has received data
        unsafe {
            // Hardware-specific implementation
            self.rx_ready()
        }
    }
    
    fn start_transmission(&mut self) {
        if self.is_tx_ready() {
            if let Some(byte) = self.tx_buffer.pop() {
                unsafe {
                    // Hardware-specific implementation
                    self.transmit_byte(byte);
                }
            }
        }
    }
    
    // Hardware-specific methods
    unsafe fn set_baud_rate(&self, _baud_rate: u32) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_data_bits(&self, _data_bits: DataBits) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_parity(&self, _parity: Parity) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_stop_bits(&self, _stop_bits: StopBits) {
        // Implementation depends on target hardware
    }
    
    unsafe fn transmit_byte(&self, _byte: u8) {
        // Implementation depends on target hardware
    }
    
    unsafe fn tx_ready(&self) -> bool {
        // Implementation depends on target hardware
        false
    }
    
    unsafe fn rx_ready(&self) -> bool {
        // Implementation depends on target hardware
        false
    }
}

SPI Communication

[spi_communication]
master_slave: true
clock_polarity: true
data_transfer: true
[spi_implementation]
// SPI configuration
pub struct SpiConfig {
    clock_speed: u32,
    mode: SpiMode,
    bit_order: BitOrder,
}
#[derive(Clone, Copy)]
pub enum SpiMode {
    Mode0, // CPOL=0, CPHA=0
    Mode1, // CPOL=0, CPHA=1
    Mode2, // CPOL=1, CPHA=0
    Mode3, // CPOL=1, CPHA=1
}
#[derive(Clone, Copy)]
pub enum BitOrder {
    MsbFirst,
    LsbFirst,
}
// SPI peripheral
pub struct Spi {
    config: SpiConfig,
    cs_pin: Option<Pin>,
}
impl Spi {
    pub fn new(config: SpiConfig) -> Self {
        let mut spi = Self {
            config,
            cs_pin: None,
        };
        spi.configure();
        spi
    }
    
    pub fn set_cs_pin(&mut self, pin: Pin) {
        self.cs_pin = Some(pin);
    }
    
    fn configure(&mut self) {
        // Configure SPI hardware
        unsafe {
            // Hardware-specific implementation
            self.set_clock_speed(self.config.clock_speed);
            self.set_mode(self.config.mode);
            self.set_bit_order(self.config.bit_order);
        }
    }
    
    pub fn transfer(&mut self, data: &[u8], response: &mut [u8]) -> Result<usize, &'static str> {
        if data.len() != response.len() {
            return Err("Data and response lengths must match");
        }
        
        // Assert chip select
        if let Some(ref mut cs) = self.cs_pin {
            cs.set_low();
        }
        
        let mut transferred = 0;
        
        for (i, &byte) in data.iter().enumerate() {
            let received = unsafe {
                // Hardware-specific implementation
                self.transfer_byte(byte)
            };
            response[i] = received;
            transferred += 1;
        }
        
        // Deassert chip select
        if let Some(ref mut cs) = self.cs_pin {
            cs.set_high();
        }
        
        Ok(transferred)
    }
    
    pub fn write(&mut self, data: &[u8]) -> Result<usize, &'static str> {
        let mut response = [0u8; 256];
        let len = data.len().min(256);
        
        self.transfer(&data[..len], &mut response[..len])
    }
    
    pub fn read(&mut self, response: &mut [u8]) -> Result<usize, &'static str> {
        let data = vec![0u8; response.len()];
        self.transfer(&data, response)
    }
    
    // Hardware-specific methods
    unsafe fn set_clock_speed(&self, _speed: u32) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_mode(&self, _mode: SpiMode) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_bit_order(&self, _order: BitOrder) {
        // Implementation depends on target hardware
    }
    
    unsafe fn transfer_byte(&self, _byte: u8) -> u8 {
        // Implementation depends on target hardware
        0
    }
}

⏰ Real-Time Systems

Interrupt Handling

[interrupt_handling]
interrupt_vectors: true
priority_management: true
context_switching: true
[interrupt_implementation]
use cortex_m::interrupt;
// Interrupt vector table
#[link_section = ".vector_table.interrupts"]
#[no_mangle]
pub static INTERRUPTS: [Option<unsafe extern "C" fn()>; 240] = {
    let mut handlers = [None; 240];
    handlers[16] = Some(sys_tick_handler);
    handlers[17] = Some(pend_sv_handler);
    handlers[18] = Some(sv_call_handler);
    handlers
};
// System tick handler
#[interrupt]
fn SysTick() {
    // Increment system tick counter
    static mut TICK_COUNT: u32 = 0;
    
    unsafe {
        TICK_COUNT += 1;
        
        // Handle periodic tasks
        if TICK_COUNT % 1000 == 0 {
            // 1 second tasks
            handle_second_tasks();
        }
        
        if TICK_COUNT % 100 == 0 {
            // 100ms tasks
            handle_100ms_tasks();
        }
        
        if TICK_COUNT % 10 == 0 {
            // 10ms tasks
            handle_10ms_tasks();
        }
    }
}
// Task scheduling
pub struct Task {
    id: u32,
    priority: u8,
    period_ms: u32,
    last_run: u32,
    handler: fn(),
}
pub struct TaskScheduler {
    tasks: StackBuffer<Task, 16>,
    current_tick: u32,
}
impl TaskScheduler {
    pub fn new() -> Self {
        Self {
            tasks: StackBuffer::new(),
            current_tick: 0,
        }
    }
    
    pub fn add_task(&mut self, task: Task) -> Result<(), &'static str> {
        self.tasks.push(task)
    }
    
    pub fn run(&mut self) {
        self.current_tick += 1;
        
        // Check for tasks that need to run
        for i in 0..self.tasks.len() {
            if let Some(task) = self.tasks.get_mut(i) {
                if self.current_tick - task.last_run >= task.period_ms {
                    task.handler();
                    task.last_run = self.current_tick;
                }
            }
        }
    }
}
// Task handlers
fn handle_10ms_tasks() {
    // High-frequency tasks
    update_sensors();
    process_inputs();
}
fn handle_100ms_tasks() {
    // Medium-frequency tasks
    update_display();
    check_alarms();
}
fn handle_second_tasks() {
    // Low-frequency tasks
    log_status();
    check_battery();
}
fn update_sensors() {
    // Read sensor data
}
fn process_inputs() {
    // Process user inputs
}
fn update_display() {
    // Update display
}
fn check_alarms() {
    // Check alarm conditions
}
fn log_status() {
    // Log system status
}
fn check_battery() {
    // Check battery level
}
// Hardware-specific interrupt handlers
extern "C" fn sys_tick_handler() {
    SysTick();
}
extern "C" fn pend_sv_handler() {
    // PendSV handler for context switching
}
extern "C" fn sv_call_handler() {
    // SVC handler for system calls
}

Real-Time Constraints

[real_time_constraints]
deadline_management: true
priority_scheduling: true
resource_sharing: true
[real_time_implementation]
// Real-time task with deadline
pub struct RealTimeTask {
    id: u32,
    priority: u8,
    deadline_ms: u32,
    execution_time_ms: u32,
    last_deadline: u32,
    missed_deadlines: u32,
}
impl RealTimeTask {
    pub fn new(id: u32, priority: u8, deadline_ms: u32, execution_time_ms: u32) -> Self {
        Self {
            id,
            priority,
            deadline_ms,
            execution_time_ms,
            last_deadline: 0,
            missed_deadlines: 0,
        }
    }
    
    pub fn check_deadline(&mut self, current_time: u32) -> bool {
        if current_time - self.last_deadline >= self.deadline_ms {
            self.last_deadline = current_time;
            true
        } else {
            false
        }
    }
    
    pub fn mark_deadline_missed(&mut self) {
        self.missed_deadlines += 1;
    }
    
    pub fn get_utilization(&self) -> f32 {
        self.execution_time_ms as f32 / self.deadline_ms as f32
    }
}
// Priority-based scheduler
pub struct PriorityScheduler {
    tasks: StackBuffer<RealTimeTask, 16>,
    current_time: u32,
}
impl PriorityScheduler {
    pub fn new() -> Self {
        Self {
            tasks: StackBuffer::new(),
            current_time: 0,
        }
    }
    
    pub fn add_task(&mut self, task: RealTimeTask) -> Result<(), &'static str> {
        self.tasks.push(task)
    }
    
    pub fn schedule(&mut self) -> Option<&mut RealTimeTask> {
        self.current_time += 1;
        
        // Find highest priority task that needs to run
        let mut highest_priority_task: Option<&mut RealTimeTask> = None;
        let mut highest_priority = 0;
        
        for i in 0..self.tasks.len() {
            if let Some(task) = self.tasks.get_mut(i) {
                if task.check_deadline(self.current_time) && task.priority > highest_priority {
                    highest_priority = task.priority;
                    highest_priority_task = Some(task);
                }
            }
        }
        
        highest_priority_task
    }
    
    pub fn run_task(&mut self, task: &mut RealTimeTask) {
        // Simulate task execution
        let start_time = self.current_time;
        
        // Check if task can complete before deadline
        if start_time + task.execution_time_ms <= start_time + task.deadline_ms {
            // Task can complete on time
            self.current_time += task.execution_time_ms;
        } else {
            // Task will miss deadline
            task.mark_deadline_missed();
            self.current_time += task.execution_time_ms;
        }
    }
}
// Resource sharing with priority inheritance
pub struct Resource {
    id: u32,
    owner: Option<u32>,
    ceiling_priority: u8,
}
impl Resource {
    pub fn new(id: u32, ceiling_priority: u8) -> Self {
        Self {
            id,
            owner: None,
            ceiling_priority,
        }
    }
    
    pub fn acquire(&mut self, task_id: u32, task_priority: u8) -> bool {
        if self.owner.is_none() {
            self.owner = Some(task_id);
            true
        } else {
            false
        }
    }
    
    pub fn release(&mut self, task_id: u32) -> bool {
        if self.owner == Some(task_id) {
            self.owner = None;
            true
        } else {
            false
        }
    }
    
    pub fn is_available(&self) -> bool {
        self.owner.is_none()
    }
}

🔋 Power Management

Low Power Modes

[power_management]
sleep_modes: true
power_optimization: true
wakeup_sources: true
[power_implementation]
// Power management states
#[derive(Clone, Copy)]
pub enum PowerMode {
    Run,
    Sleep,
    Stop,
    Standby,
}
// Power manager
pub struct PowerManager {
    current_mode: PowerMode,
    wakeup_sources: StackBuffer<WakeupSource, 8>,
}
impl PowerManager {
    pub fn new() -> Self {
        Self {
            current_mode: PowerMode::Run,
            wakeup_sources: StackBuffer::new(),
        }
    }
    
    pub fn enter_sleep_mode(&mut self, mode: PowerMode) {
        // Configure wakeup sources
        self.configure_wakeup_sources();
        
        // Enter sleep mode
        match mode {
            PowerMode::Sleep => self.enter_sleep(),
            PowerMode::Stop => self.enter_stop(),
            PowerMode::Standby => self.enter_standby(),
            PowerMode::Run => return,
        }
        
        self.current_mode = mode;
    }
    
    pub fn add_wakeup_source(&mut self, source: WakeupSource) -> Result<(), &'static str> {
        self.wakeup_sources.push(source)
    }
    
    fn configure_wakeup_sources(&self) {
        // Configure hardware wakeup sources
        for i in 0..self.wakeup_sources.len() {
            if let Some(source) = self.wakeup_sources.get(i) {
                source.enable();
            }
        }
    }
    
    fn enter_sleep(&self) {
        // Enter sleep mode
        unsafe {
            // Hardware-specific implementation
            self.set_sleep_mode();
            cortex_m::asm::wfi();
        }
    }
    
    fn enter_stop(&self) {
        // Enter stop mode
        unsafe {
            // Hardware-specific implementation
            self.set_stop_mode();
            cortex_m::asm::wfi();
        }
    }
    
    fn enter_standby(&self) {
        // Enter standby mode
        unsafe {
            // Hardware-specific implementation
            self.set_standby_mode();
            cortex_m::asm::wfi();
        }
    }
    
    // Hardware-specific methods
    unsafe fn set_sleep_mode(&self) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_stop_mode(&self) {
        // Implementation depends on target hardware
    }
    
    unsafe fn set_standby_mode(&self) {
        // Implementation depends on target hardware
    }
}
// Wakeup source abstraction
pub struct WakeupSource {
    source_type: WakeupSourceType,
    enabled: bool,
}
#[derive(Clone, Copy)]
pub enum WakeupSourceType {
    GpioInterrupt(u8, u8), // port, pin
    TimerInterrupt,
    UartInterrupt,
    RtcAlarm,
}
impl WakeupSource {
    pub fn new(source_type: WakeupSourceType) -> Self {
        Self {
            source_type,
            enabled: false,
        }
    }
    
    pub fn enable(&mut self) {
        self.enabled = true;
        // Enable hardware wakeup source
        unsafe {
            self.enable_hardware_source();
        }
    }
    
    pub fn disable(&mut self) {
        self.enabled = false;
        // Disable hardware wakeup source
        unsafe {
            self.disable_hardware_source();
        }
    }
    
    // Hardware-specific methods
    unsafe fn enable_hardware_source(&self) {
        // Implementation depends on target hardware
    }
    
    unsafe fn disable_hardware_source(&self) {
        // Implementation depends on target hardware
    }
}

🎯 Best Practices

1. Memory Management

- Use static allocation when possible - Minimize heap usage - Implement custom allocators - Monitor stack usage

2. Real-Time Constraints

- Design for worst-case execution time - Use priority-based scheduling - Implement deadline monitoring - Handle resource contention

3. Power Optimization

- Use appropriate sleep modes - Minimize active time - Optimize clock frequencies - Implement wakeup strategies

4. Hardware Abstraction

- Create portable abstractions - Separate hardware-specific code - Use trait-based interfaces - Implement proper error handling

5. Testing and Debugging

- Use hardware-in-the-loop testing - Implement logging mechanisms - Use debug interfaces - Test interrupt handling

Embedded systems development with TuskLang and Rust provides the safety and performance needed for reliable real-time applications while maintaining the flexibility to work with various hardware platforms.