Asynchronous Communication

Definition

Asynchronous communication is a method of data transmission where the sender and receiver do not need to be synchronized with each other in time. This type of communication allows for data to be sent and received at different times, making it ideal for situations where real-time interaction is not necessary. In the context of serial communication, it enables devices to exchange information without requiring both parties to be ready at the same moment, enhancing flexibility in data exchange.

5 Must Know Facts For Your Next Test

1. Asynchronous communication does not require a clock signal for synchronization, which simplifies wiring and connection requirements.
2. It often uses start bits and stop bits to mark the beginning and end of data packets, ensuring that the receiving device can correctly interpret the incoming data.
3. Data can be sent in various formats, commonly 8 bits, with optional parity bits for error checking.
4. Asynchronous protocols are generally simpler and less expensive to implement compared to synchronous protocols due to their relaxed timing requirements.
5. This form of communication is widely used in serial interfaces like RS-232 and USB, which facilitates communication between computers and peripherals.

Review Questions

• How does asynchronous communication differ from synchronous communication, particularly in terms of data transmission?
  • Asynchronous communication differs from synchronous communication primarily in its lack of timing coordination between the sender and receiver. In asynchronous communication, data is transmitted without a shared clock signal, allowing devices to send and receive information independently. This flexibility means that the receiver can process incoming data at its own pace, as long as it correctly identifies the start and stop bits that frame each data packet.
• Evaluate the advantages and disadvantages of using asynchronous communication in embedded systems design.
  • The main advantages of asynchronous communication include its simplicity, reduced wiring requirements, and lower cost of implementation compared to synchronous methods. It allows devices to communicate over longer distances without needing complex timing synchronization. However, its disadvantages include potential delays due to the lack of real-time interaction and possible inefficiencies in high-speed data transfer scenarios where more robust synchronization might be beneficial.
• Discuss how asynchronous communication can impact the overall performance of an embedded system, especially in multi-device environments.
  • In multi-device environments, asynchronous communication can significantly enhance system performance by allowing devices to operate independently without waiting for a central clock signal. This independence can lead to increased throughput since multiple devices can communicate simultaneously or at their own pace. However, if not managed properly, this could also introduce challenges like data collisions or delays in processing as devices might misinterpret incoming signals without precise synchronization mechanisms. Balancing these factors is crucial for optimizing the performance of an embedded system.

Related terms

UART:

Universal Asynchronous Receiver-Transmitter, a hardware device that handles asynchronous serial communication, converting parallel data from a microcontroller to serial format.

Baud Rate: The rate at which information is transmitted over a communication channel, typically measured in bits per second (bps).

Start and Stop Bits: Special bits used in asynchronous communication to indicate the beginning (start bit) and end (stop bit) of a data byte being transmitted.