GPIO pin concepts for hardware abstraction. More...
#include <concepts>
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Namespaces | |
| namespace | epaper |
| namespace | epaper::hal |
Concepts | |
| concept | epaper::hal::DigitalOutput |
| concept | epaper::hal::DigitalInput |
Detailed Description
GPIO pin concepts for hardware abstraction.
Defines C++20 concepts for digital input/output pins, enabling generic driver code that works with any GPIO implementation.
Design Philosophy:
Hardware Abstraction via Concepts
├─ Platform Independence: Drivers work with any GPIO backend
├─ Mockability: Easy to substitute mock pins for testing
├─ Zero Overhead: Concepts compile to direct calls (no vtable)
└─ Type Safety: Compile-time validation of pin capabilities
Concept Hierarchy:
DigitalOutput: write(bool) -> void
DigitalInput: read() -> bool
Typical Implementations:
- Production: libgpiod v2 wrapper (Linux GPIO character device)
- Testing: MockPin (in-memory state, no hardware)
- Embedded: Platform-specific register writes (ARM, RISC-V)
Pin Semantics:
write(true): Set pin to logic HIGH (typically 3.3V or 5V)write(false): Set pin to logic LOW (typically 0V/GND)read(): Sample current pin state (true=HIGH, false=LOW)
No Buffering:
- All operations are immediate (no internal buffering)
write()may not guarantee signal stability until next call- Debouncing/filtering must be done externally
