Discuss the purpose and operation of a Universal Asynchronous Receiver/Transmitter (UART).
1 Answer
A Universal Asynchronous Receiver/Transmitter, commonly known as UART, is an essential hardware component used for serial communication between devices. It facilitates the transfer of data between a microcontroller or a computer and other peripheral devices, such as sensors, displays, modems, GPS modules, and more. UART is popularly employed in various applications, including embedded systems, IoT devices, communication interfaces, and industrial automation.
Purpose of UART:
The primary purpose of a UART is to enable asynchronous serial communication, meaning the data is transmitted in a stream of bits without a shared clock signal between the sender and receiver. Instead, both the transmitting and receiving devices agree upon a specific baud rate (bits per second) to synchronize data transmission.
Operation of UART:
Data framing: UART frames the data to be transmitted into packets known as "frames." Each frame usually consists of a start bit, data bits (typically 8 bits), an optional parity bit (for error checking), and one or more stop bits. The start bit indicates the beginning of a new frame, while the stop bit(s) signal the end of the frame.
Asynchronous transmission: Asynchronous communication means that data is sent without a continuous clock signal. Both the transmitter and receiver devices must agree upon the same baud rate to ensure synchronization. During transmission, the sender transmits the data bits along with the start and stop bits, and the receiver samples the bits based on the agreed baud rate to reconstruct the original data.
Serial-to-Parallel and Parallel-to-Serial conversion: The UART performs serial-to-parallel conversion at the transmitting end and parallel-to-serial conversion at the receiving end. This means it takes a byte of parallel data (usually from a microcontroller) and sends it as a stream of bits over a single wire (TX) to the receiving device. On the receiving side, it takes the incoming serial stream and converts it back into parallel bytes for the receiver's use.
Error handling (optional): UARTs may include optional error-checking mechanisms like parity bits. Parity bits can be set to odd, even, or none, depending on the desired level of error detection. The receiver can then use the parity bit to check for transmission errors, although more robust error-checking methods like CRC (Cyclic Redundancy Check) are commonly used in modern communication protocols.
Flow control (optional): Some UARTs support flow control mechanisms, such as hardware flow control (using RTS/CTS signals) or software flow control (using XON/XOFF characters). These mechanisms help prevent data overflow or loss when the transmitting device sends data too quickly for the receiving device to handle.
In summary, a UART provides a simple and reliable means of serial communication between devices using asynchronous transmission. It is widely used due to its simplicity, ease of implementation, and broad compatibility with various devices and communication protocols.
Purpose of UART:
The primary purpose of a UART is to enable asynchronous serial communication, meaning the data is transmitted in a stream of bits without a shared clock signal between the sender and receiver. Instead, both the transmitting and receiving devices agree upon a specific baud rate (bits per second) to synchronize data transmission.
Operation of UART:
Data framing: UART frames the data to be transmitted into packets known as "frames." Each frame usually consists of a start bit, data bits (typically 8 bits), an optional parity bit (for error checking), and one or more stop bits. The start bit indicates the beginning of a new frame, while the stop bit(s) signal the end of the frame.
Asynchronous transmission: Asynchronous communication means that data is sent without a continuous clock signal. Both the transmitter and receiver devices must agree upon the same baud rate to ensure synchronization. During transmission, the sender transmits the data bits along with the start and stop bits, and the receiver samples the bits based on the agreed baud rate to reconstruct the original data.
Serial-to-Parallel and Parallel-to-Serial conversion: The UART performs serial-to-parallel conversion at the transmitting end and parallel-to-serial conversion at the receiving end. This means it takes a byte of parallel data (usually from a microcontroller) and sends it as a stream of bits over a single wire (TX) to the receiving device. On the receiving side, it takes the incoming serial stream and converts it back into parallel bytes for the receiver's use.
Error handling (optional): UARTs may include optional error-checking mechanisms like parity bits. Parity bits can be set to odd, even, or none, depending on the desired level of error detection. The receiver can then use the parity bit to check for transmission errors, although more robust error-checking methods like CRC (Cyclic Redundancy Check) are commonly used in modern communication protocols.
Flow control (optional): Some UARTs support flow control mechanisms, such as hardware flow control (using RTS/CTS signals) or software flow control (using XON/XOFF characters). These mechanisms help prevent data overflow or loss when the transmitting device sends data too quickly for the receiving device to handle.
In summary, a UART provides a simple and reliable means of serial communication between devices using asynchronous transmission. It is widely used due to its simplicity, ease of implementation, and broad compatibility with various devices and communication protocols.