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Universal Asynchronous Receiver-transmitter
A universal asynchronous receiver-transmitter (UART ) is a peripheral 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 signaling levels are handled by a driver circuit external to the UART. Common signal levels are RS-232, RS-485, and raw TTL for short debugging links. Early teletypewriters used current loops. It was one of the earliest computer communication devices, used to attach teletypewriters for an operator console. It was also an early hardware system for the Internet. A UART is usually implemented in an integrated circuit (IC) and used for serial communications over a computer or peripheral device serial port. One or more UART peripherals are commonly integrated in microcontroller chips. Specialised UARTs are use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UART Block Diagram
A universal asynchronous receiver-transmitter (UART ) is a peripheral 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 signaling levels are handled by a driver circuit external to the UART. Common signal levels are RS-232, RS-485, and raw TTL for short debugging links. Early teletypewriters used current loops. It was one of the earliest computer communication devices, used to attach teletypewriters for an operator console. It was also an early hardware system for the Internet. A UART is usually implemented in an integrated circuit (IC) and used for serial communications over a computer or peripheral device serial port. One or more UART peripherals are commonly integrated in microcontroller chips. Specialised UARTs are used for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OSI Model
The Open Systems Interconnection (OSI) model is a reference model developed by the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems interconnection." In the OSI reference model, the components of a communication system are distinguished in seven abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model describes communications from the physical implementation of transmitting bits across a transmission medium to the highest-level representation of data of a distributed application. Each layer has well-defined functions and semantics and serves a class of functionality to the layer above it and is served by the layer below it. Established, well-known communication protocols are decomposed in software development into the model's hierarchy of function calls. The Internet protocol suite as defined in and is a model of net ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrated Circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components are etched onto a small, flat piece ("chip") of semiconductor material, usually silicon. Integrated circuits are used in a wide range of electronic devices, including computers, smartphones, and televisions, to perform various functions such as processing and storing information. They have greatly impacted the field of electronics by enabling device miniaturization and enhanced functionality. Integrated circuits are orders of magnitude smaller, faster, and less expensive than those constructed of discrete components, allowing a large transistor count. The IC's mass production capability, reliability, and building-block approach to integrated circuit design have ensured the rapid adoption of standardized ICs in place of designs using discre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Digital
Western Digital Corporation is an American data storage company headquartered in San Jose, California. Established in 1970, the company is one of the world's largest manufacturers of hard disk drives (HDDs). History 1970s Western Digital was founded on April 23, 1970, by Alvin B. Phillips, a Motorola employee, as General Digital Corporation, initially a manufacturer of MOS test equipment. It was originally based in Newport Beach, California, shortly thereafter moving to Santa Ana, California, and would go on to become one of the largest technology firms headquartered in Orange County. It rapidly became a specialty semiconductor maker, with start-up capital provided by several individual investors and industrial giant Emerson Electric. Around July 1971, it adopted its current name and soon introduced its first product, the ''WD1402A'' UART. During the early 1970s, the company focused on making and selling calculator chips, and by 1975, Western Digital was the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Flow Control
Software flow control is a method of flow control used in computer data links, especially RS-232 serial. It uses special codes, transmitted in-band, over the primary communications channel. These codes are generally called XOFF and XON (from "transmit off" and "transmit on", respectively). Thus, "software flow control" is sometimes called "XON/XOFF flow control". This is in contrast to flow control via dedicated out-of-band signals — " hardware flow control" — such as RS-232 RTS/CTS. Representation For systems using the ASCII character code, XOFF is generally represented using a character or byte with decimal value 19; XON with value 17. The ASCII standard does not reserve any control characters for use as XON/XOFF specifically. However, it does provide four generic "device control" characters (DC1 through DC4). The Teletype Model 33 ASR adopted two of these, DC3 and DC1, for use as XOFF and XON, respectively. This usage was copied by others, and is now a de fac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potentiometer
A potentiometer is a three- terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. It is also used in speed control of fans. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load. Nomenclature Some terms in the electronics industry used to describe certain types of potentiometers are: * Pot: ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sampling (signal Processing)
In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. A common example is the conversion of a sound wave to a sequence of "samples". A sample is a value of the signal at a point in time and/or space; this definition differs from the term's usage in statistics, which refers to a set of such values. A sampler is a subsystem or operation that extracts samples from a continuous signal. A theoretical ideal sampler produces samples equivalent to the instantaneous value of the continuous signal at the desired points. The original signal can be reconstructed from a sequence of samples, up to the Nyquist limit, by passing the sequence of samples through a reconstruction filter. Theory Functions of space, time, or any other dimension can be sampled, and similarly in two or more dimensions. For functions that vary with time, let s(t) be a continuous function (or "signal") to be sampled, and let sampling be performed by measuring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-1
The PDP-1 (Programmed Data Processor-1) is the first computer in Digital Equipment Corporation's PDP series and was first produced in 1959. It is known for being the most important computer in the creation of hacker culture at the Massachusetts Institute of Technology, Bolt, Beranek and Newman, and elsewhere. The PDP-1 is the original hardware for one of the first video games, Steve Russell's 1962 game '' Spacewar!.'' Description The PDP-1 uses an 18-bit word size and has 4096 words as standard main memory (equivalent in bit size to 9,216 eight-bit bytes, but in character size to 12,388 bytes since the system actually divides an 18-bit word into three six-bit characters), upgradable to 65,536 words. The magnetic-core memory's cycle time is 5.35 microseconds (corresponding roughly to a clock speed of 187 kilohertz); consequently most arithmetic instructions take 10.7 microseconds (93,458 operations per second) because they use two memory cycles: the first to fetch the instruc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmed Data Processor
Programmed Data Processor (PDP), referred to by some customers, media and authors as "Programmable Data Processor," is a term used by the Digital Equipment Corporation from 1957 to 1990 for several lines of minicomputers. The name "PDP" intentionally avoids the use of the term "computer". At the time of the first PDPs, computers had a reputation of being large, complicated, and expensive machines. The venture capitalists behind Digital (especially Georges Doriot) would not support Digital's attempting to build a "computer" and the term "minicomputer" had not yet been coined. So instead, Digital used their existing line of logic modules to build a ''Programmed Data Processor'' and aimed it at a market that could not afford the larger computers. The various PDP machines can generally be grouped into families based on word length. Series Members of the PDP series include: ;PDP-1: The original PDP, an 18-bit computing, 18-bit four-19-inch rack, rack machine used in early tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until he was forced to resign in 1992, after the company had gone into precipitous decline. The company produced many different product lines over its history. It is best known for the work in the minicomputer market starting in the early 1960s. The company produced a series of machines known as the Programmed Data Processor, PDP line, with the PDP-8 and PDP-11 being among the most successful minis in history. Their success was only surpassed by another DEC product, the late-1970s VAX "supermini" systems that were designed to replace the PDP-11. Although a number of competitors had successfully competed with Digital through the 1970s, the VAX cemented the company's place as a leading vendor in the computer space. As microcomputers improved in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gordon Bell
Chester Gordon Bell (August 19, 1934 – May 17, 2024) was an American electrical engineer and manager. An early employee of Digital Equipment Corporation (DEC), from 1960–1966, Bell designed several of their PDP machines and later served as the company's Vice President of Engineering from 1972–1983, overseeing development of the VAX computer systems. Bell's later career included roles as an entrepreneur, investor, founding Assistant Director of NSF's Computing and Information Science and Engineering Directorate from 1986–1987, and researcher emeritus at Microsoft Research from 1995–2015. Early life and education Gordon Bell was born in Kirksville, Missouri. He grew up helping with the family business, Bell Electric, repairing appliances and wiring homes. Bell received a BS (1956), and MS (1957) in electrical engineering from MIT. He then went to the New South Wales University of Technology (now UNSW) in Australia on a Fulbright Scholarship in 1957–58, where he ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Character Encoding
Character encoding is the process of assigning numbers to graphical character (computing), characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical values that make up a character encoding are known as code points and collectively comprise a code space or a code page. Early character encodings that originated with optical or electrical telegraphy and in early computers could only represent a subset of the characters used in written languages, sometimes restricted to Letter case, upper case letters, Numeral system, numerals and some punctuation only. Over time, character encodings capable of representing more characters were created, such as ASCII, the ISO/IEC 8859 encodings, various computer vendor encodings, and Unicode encodings such as UTF-8 and UTF-16. The Popularity of text encodings, most popular character encoding on the World Wide Web is UTF-8, which is used in 98.2% of surve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
