Here is the detailed information of Serial Communication:
Serial communication is the process of sequentially transferring the information/bits on the same channel. Due to this, the cost of wire will be reduced, but it slows the transmission speed.
• Generally, communication can be described as the process of interchanging information between individuals in the form of audio, video, verbal words, and written documents. The serial protocol is run on every device that can be our mobile, personal computers, and many more with the help of following some protocols.
• The protocol is a type of reliable and secure form of communication that contains a set of rules addressed with the help of a source host and a destination host. In serial communication, binary pulses are used to show the data. Binary contains the two numbers 0 and 1. 0 is used to show the LOW or 0 Volts, and 1 is used to show the HIGH or 5 Volts.
Here’s how serial communication typically works:
‣ Serial Communication Interface:
Serial communication involves two devices: a transmitter and a receiver.
The transmitter sends data serially, and the receiver receives and interprets the data.
‣ Serial Data Format:
Data is transmitted as a stream of bits, with each bit being sent one after the other, typically starting with the least significant bit (LSB) and ending with the most significant bit (MSB).
In addition to the data bits, serial communication may include control bits such as start bits, stop bits, and parity bits to facilitate synchronization, framing, and error detection.
‣ Baud Rate:
The baud rate (or bit rate) defines the speed at which data is transmitted over the serial communication channel.
It represents the number of bits transmitted per second (bps) and determines the rate at which the transmitter and receiver synchronize their clocks.
‣ Synchronization:
Synchronization between the transmitter and receiver is essential to ensure accurate data transmission.
Start bits are typically used to signal the beginning of a data frame, allowing the receiver to synchronize its clock with the transmitter’s clock.
Stop bits mark the end of a data frame and provide additional time for the receiver to prepare for the next data frame.
‣ Error Detection and Correction:
Parity bits may be used for error detection in serial communication.
The parity bit is added to each data frame, and its value is adjusted to ensure that the total number of bits with a value of 1 (or 0, depending on the parity scheme) is either odd or even.
The receiver can detect errors by comparing the received parity bit with the expected parity.
‣ Protocols:
Various serial communication protocols exist, each defining rules and conventions for data transmission, framing, synchronization, and error detection.
Common serial communication protocols include RS-232, RS-485, UART (Universal Asynchronous Receiver-Transmitter), SPI (Serial Peripheral Interface), and I2C (Inter-Integrated Circuit).
‣ Applications:
Serial communication is used in a wide range of applications, including serial port communication between computers and peripherals, serial data transmission in networking (e.g., RS-232 and RS-485), serial communication between microcontrollers and sensors, and serial communication in industrial automation and control systems.
The serial communication can either be asynchronous or synchronous:
Asynchronous:
In asynchronous communication, the groups of bits will be treated as an independent unit, and these data bits will be sent at any point in time. In order to make synchronization between sender and receiver, the stop bits and start bits are used between the data bytes.
• These bits are useful to ensure that the data is correctly sent. The time taken by data bits of sender and receiver is not constant, and the time between transmissions will be provided by the gaps.
• In asynchronous communication, we don’t require synchronization between the sender and receiver devices, which is the main advantage of asynchronous communication. This method is also cost-effective. In this method, there can be a case when data transmission is slow, but it is not compulsory, and it is the main disadvantage of the asynchronous method.
Synchronous:
In synchronous communication, the frames or data will be constructed with the help of combining the groups of bits. That frames will be continuously sent in time with a master clock.
• It uses a synchronized clock frequency to operate the data of sender or receiver. In synchronous communication, there is no need to use the gaps, start bits and stop bits. The time taken by the sender and receiver is synced that’s why the frequency of timing error will be less, and the data will move faster.
• On the basis of the timing being synced correctly between the sender and receiver devices, the data accuracy is totally dependent. The synchronous serial transmission is more expensive as compared to asynchronous serial transmission.
Some Terms used in serial Communication:
‣ Data Communication Processor (DCP):
A data communication processor is a specialized hardware or software component responsible for managing the exchange of data between computing devices in a network. It typically handles tasks such as data formatting, error checking, and routing.
‣ Modem (Modulator-Demodulator):
A modem is a device that modulates analog signals into digital signals for transmission over communication channels (such as telephone lines or fiber optic cables) and demodulates incoming digital signals back into analog signals for reception. Modems enable computers and other digital devices to communicate over long distances using existing analog infrastructure.
‣ Block Transfer:
Block transfer refers to the transmission of data in discrete, fixed-size blocks or packets rather than as a continuous stream. This method is commonly used in data communication systems to improve efficiency and reliability by organizing data into manageable chunks for transmission and processing.
‣ CRC (Cyclic Redundancy Check):
CRC is a type of error-detecting code used in digital communication systems to detect errors in transmitted data. It involves appending a checksum to the data being transmitted, which is computed based on the data contents. Upon reception, the receiver recalculates the checksum and compares it to the received checksum to determine if any errors occurred during transmission.
‣ Full-Duplex:
Full-duplex communication allows for simultaneous bidirectional data transmission, meaning that data can be sent and received simultaneously between two communicating parties. This contrasts with half-duplex communication, where data can only be transmitted in one direction at a time.
‣ Protocol:
A protocol is a set of rules and conventions governing the format, timing, sequencing, and error control of data exchange between computing devices in a network. Protocols define how data is transmitted, received, and interpreted, enabling interoperability and effective communication between different systems and devices.
Character- Oriented Protocol:
Character-Oriented Protocol (COP) refers to a type of communication protocol where data is organized and transmitted based on individual characters rather than larger data packets.
• Character-oriented protocols are often used in scenarios where data needs to be transmitted in a simple and straightforward manner, such as in serial communication over RS-232 connections or in older networking technologies like dial-up modems.
• These protocols are relatively simple to implement and are well-suited for applications with low data throughput requirements or where real-time processing is necessary.
‣ SYN Character:
It stands for Synchronize Character. The SYN Character serves as synchronizing agent between the transmitter and receiver.
‣ ASCII Communication Control Characters:
‣ Typical Transmission from a Terminal to Processor:
‣ Typical Transmission from Processor to Terminal:
Data Transparency:
Data transparency in microprocessors refers to the concept of making the flow of data within the processor transparent or easily understandable to the programmer or the system designer.
‣ DLE Character:
The DLE character is used to prevent such misinterpretations.
• It’s typically a reserved control character that indicates that the following character is not to be interpreted as a control character. Instead, it signals that it’s part of the data payload.
• The DLE character ensures that data is transmitted transparently, without interference or misinterpretation of control characters.
Bit- Oriented Protocol:
A bit-oriented protocol is a type of communication protocol where data is transmitted and received at the bit level.
• Bit-oriented protocols are often used in low-level communication systems where precise control over individual bits is necessary, such as in serial communication interfaces like RS-232 or in certain network protocols.
• These protocols typically define rules for how individual bits are encoded, transmitted, and interpreted by the communicating devices.
• Example of bit- oriented protocol: HDLC (High-Level Data Link Control, SDLC (synchronous data link control), ADCCP(advanced data communication control procedure).
‣ 8-bit flag:
An 8-bit flag refers to a binary digit (bit) that can either be in a state of 0 or 1.
• In an 8-bit flag, there are 8 individual bits available for such flags, allowing for a total of 256 possible combinations (2^8).
• These flags might be used for various purposes such as error detection, status reporting, or configuration settings within a computer program or system.
‣ Zero insertion:
Zero insertion refers to a process in which zeros are added to a data stream or sequence in order to maintain specific formatting or synchronization requirements.
• This process is commonly employed in telecommunications and digital communications systems
• For example, in certain types of data transmission protocols, such as asynchronous transmission, zero insertion may be used to ensure that the receiver can accurately interpret the data being transmitted.
‣ Control field:
A control field is a part of a data structure or communication protocol that contains control information used for managing the transmission or processing of data.
• Control fields are often found in packet-based communication systems such as network protocols.
• The control field is usually distinct from the actual data being transmitted and is used by the receiving system to interpret and process the incoming data correctly.
Bus Standards:
Bus standards refer to the specifications and protocols that define how different devices communicate and exchange data over a computer bus.
• A computer bus is a subsystem that allows various components within a computer system to communicate with each other, such as the CPU, memory, storage devices, and peripherals.
‣ USB (Universal Serial Bus):
USB is one of the most widely used interfaces for connecting peripherals to computers. It’s hot-swappable, meaning devices can be plugged and unplugged without restarting the computer.
• USB supports multiple data transfer rates, with the latest iterations offering high-speed data transfer up to 20 Gbps (USB 3.2 Gen 2×2).
• It’s versatile, supporting a wide range of devices such as keyboards, mice, printers, external storage, cameras, and more.
‣ FireWire (IEEE 1394):
Developed by Apple, FireWire is another high-speed interface used for connecting peripherals to computers, particularly popular in professional audio/video applications.
• FireWire supports data transfer rates ranging from 100 Mbps to 3.2 Gbps.
• It allows for peer-to-peer connections, enabling devices to communicate directly without involving the computer’s CPU.
• While it was widely used in the past, USB has largely supplanted FireWire in consumer applications due to its lower cost and wider compatibility.
‣ SCSI (Small Computer System Interface):
SCSI is an older standard primarily used for connecting hard drives, tape drives, and other high-performance peripherals.
• It supports high data transfer rates and allows for multiple devices to be connected to a single SCSI bus.
• SCSI has various iterations like SCSI-1, SCSI-2, SCSI-3, Ultra SCSI, Ultra2 SCSI, Ultra3 SCSI (also known as Ultra160 or SCSI-3), Ultra320 SCSI, and Serial Attached SCSI (SAS).
• Despite its historical significance, SCSI has largely been replaced by SATA and SAS for storage devices due to their cost-effectiveness and simplicity.
‣ SATA (Serial Advanced Technology Attachment):
SATA is a widely used interface for connecting storage devices like hard drives and solid-state drives (SSDs) to a computer’s motherboard.
• It offers high-speed data transfer rates (up to 6 Gbps in SATA III) and is hot-swappable.
• SATA cables are thin and flexible, making them easier to route within a computer chassis compared to the bulkier cables used in older interfaces like PATA (Parallel ATA).
