Asynchronous serial communication

BASIC Stamp Microcontroller

Published in Ferat Sahin, Pushkin Kachroo, Practical and Experimental Robotics, 2017

The SEROUT command is used to send asynchronous serial data. The term asynchronous means “no clock.” More specifically, asynchronous serial communication means data is transmitted and received without the use of a separate “clock” wire. Data can be sent using only two wires: one for data and one for the ground. In contrast, synchronous serial communication uses at least three wires: one for the clock, one for data, and one for the ground. The PC’s serial ports (also called COM ports or RS-232 ports) use asynchronous serial communication. RS-232 is the electrical specification for the signals that PC serial ports use. Unlike normal logic, where 5 volts is logic 1 and 0 volts is logic 0, RS-232 uses -12 volts for logic 1 and +12 volts for logic 0. This specification allows communication over longer wire lengths without amplification.

Enhanced performance of the mechanical respiratory system by FPGA-digital based on PID Controller

View Article

Journal Information

Published in Cogent Engineering, 2023

Dang Quy Phan, Ha Quang Thinh Ngo

UART, Universal asynchronous receiver transmitter, is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. It sends data bits one by one, from the least significant to the most significant, framed by start and stop bits so that precise timing is handled by the communication channel. The electric signalling levels are handled by a driver circuit external to the UART. Two common signal levels are RS-232, a 12-volt system, and RS-485, a 5-volt system. Early teletypewriters used current loops.

Asynchronous serial communication

Explore chapters and articles related to this topic

BASIC Stamp Microcontroller

Enhanced performance of the mechanical respiratory system by FPGA-digital based on PID Controller