Interfacing with External Devices

Interfacing with External Devices

  • Interfacing refers to the method of sharing data and control signals between the microcontroller or microprocessor and external devices or peripherals.

Types of Interfacing

  • Parallel Interfacing: Here, multiple data bits are sent simultaneously over different wires. Used for applications requiring high data transfer speed. It, however, requires more space for the additional wires.
  • Serial Interfacing: Sends one bit of data at a time sequentially. Requiring less wiring, it is used for applications where slower data transmission is acceptable.

Types of Serial Interfaces

  • SPI (Serial Peripheral Interface): Simple, fast, short distance communication interface typically used in embedded systems. It uses a master-slave configuration.
  • I2C (Inter-Integrated Circuit): A type of serial interface that allows multiple devices to communicate with the microcontroller. It’s slower than SPI, but more efficient as it requires fewer pins.
  • UART (Universal Asynchronous Receiver Transmitter): A type of connection that does not require a clock signal and can be used for long distance communication.

ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter)

  • Many sensors and output devices deal with analog signals while microcontrollers/microprocessors work with digital data. ADCs convert the analog signals into digital data for the microcontroller to process. Similarly, DACs convert the microcontroller’s digital output into analog signals for use in external devices.
  • Understanding the Resolution, Sampling Rate, and Conversion Time for ADC and DAC is important to select the right one for any specific application.

Interfacing Inputs and Outputs

  • To interface with input devices like sensors, switches, or keypads, the microcontroller must be programmed to regularly check or monitor these inputs for changes.
  • To interface with output devices like LEDs, LCDs, buzzers, or motors, the microcontroller must be programmed to control these devices based on input signals or pre-set conditions. This involves generating properly timed control signals for each type of device.