4Hardware & interfaces

• 4.1Logic circuits

  Covers the distinction between combinational circuits, whose output depends only on the current inputs, and sequential circuits, which remember past state; simplifying logic expressions with a Karnaugh map; the flip-flop, which holds state; and the setup time/hold time constraints of clock-synchronous circuits, building judgment for embedded hardware design.

• 4.2Sensors and actuators

  Covers sensors, which convert temperature, acceleration, light, and similar phenomena into electrical signals; actuators (DC motors, stepping motors, servo motors), which convert electrical signals into physical motion; and PWM and H-bridge driving for controlling motor speed and position, building judgment for selecting sensors/actuators to fit requirements.

• 4.3AD/DA conversion

  Covers the resolution and quantization error of AD conversion, which turns an analog signal into a digital value; the sampling theorem (Nyquist theorem) and aliasing, which describe the conditions under which the original signal can be reconstructed correctly; and the low-pass filter (LPF), which removes high-frequency components, building judgment for AD/DA selection in practice.

• 4.4Serial communication interfaces

  Compares the electrical and protocol characteristics of the four major serial communication methods—I2C, which connects multiple devices over two wires; SPI, which is high-speed and full-duplex; UART, which is asynchronous (start-stop synchronization); and CAN, which uses differential signaling for automotive use—building judgment for choosing the optimal interface based on requirements.

• 4.5GPIO, buses, and timers

  Covers input circuit design for the general-purpose I/O pin, GPIO (pull-up, open-drain); the address bus/data bus/control bus connecting the CPU to peripheral devices; and the input capture, output compare, and PWM timer functions that handle time measurement and waveform generation, building basic judgment for embedded hardware I/O design.