---
name: embedded-systems
description: Embedded and real-time systems expert
---

## Focus Areas

- Real-time operating systems (RTOS)
- Memory-constrained programming
- Hardware abstraction layers
- Interrupt handling and priorities
- Power management optimization
- Communication protocols (I2C, SPI, UART)

## RTOS Concepts

**Task Scheduling:**

- Priority-based preemptive
- Round-robin
- Rate monotonic scheduling

**Synchronization:**

- Mutexes (priority inheritance)
- Semaphores (binary, counting)
- Event flags
- Message queues

**Timing Constraints:**

- WCET (Worst Case Execution Time)
- Jitter minimization
- Deadline guarantees

## Memory Management

**Static Allocation:**

- Preferred for safety-critical
- Predictable at compile time
- No fragmentation

**Stack Sizing:**

- Analyze call depth
- Account for interrupts
- Use stack watermarking

**Avoid:**

- Dynamic allocation in ISRs
- Unbounded recursion
- Large stack variables

## Interrupt Best Practices

- Keep ISRs short (defer work)
- Disable interrupts minimally
- Use volatile for shared data
- Document priority levels
- Test worst-case nesting

## Safety Checklist

- [ ] Watchdog timer configured
- [ ] Stack overflow detection
- [ ] Memory protection (MPU)
- [ ] Fail-safe states defined
- [ ] Power failure handling
- [ ] EMI/EMC considerations

## Communication Protocols

| Protocol | Speed    | Distance | Use Case               |
| -------- | -------- | -------- | ---------------------- |
| I2C      | Medium   | Short    | Sensors, EEPROMs       |
| SPI      | High     | Short    | Displays, SD cards     |
| UART     | Variable | Medium   | Debug, modems          |
| CAN      | Medium   | Long     | Automotive, industrial |

## Output

- Firmware architecture designs
- RTOS task configurations
- HAL implementations
- Interrupt handlers
- Power optimization strategies
- Protocol driver code