Link level

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In computer networking, in the hierarchical structure of a primary or secondary station, link level is the conceptual level of control or data processing logic that controls the data link.

Link-level functions provide an interface between the station high-level logic and the data link. Link-level functions include (a) transmit bit injection and receive bit extraction, (b) address and control field interpretation, (c) command response generation, transmission and interpretation, and (d) frame check sequence computation and interpretation.

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Processor design is a subfield of computer science and computer engineering (fabrication) that deals with creating a processor, a key component of computer hardware.

In processor design, microcode serves as an intermediary layer situated between the central processing unit (CPU) hardware and the programmer-visible instruction set architecture of a computer, also known as its machine code. It consists of a set of hardware-level instructions that implement the higher-level machine code instructions or control internal finite-state machine sequencing in many digital processing components. While microcode is utilized in Intel and AMD general-purpose CPUs in contemporary desktops and laptops, it functions only as a fallback path for scenarios that the faster hardwired control unit is unable to manage.

<span class="mw-page-title-main">Microcontroller</span> Small computer on a single integrated circuit

A microcontroller or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs along with memory and programmable input/output peripherals. Program memory in the form of NOR flash, OTP ROM, or ferroelectric RAM is also often included on the chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general-purpose applications consisting of various discrete chips.

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<span class="mw-page-title-main">Programmable logic controller</span> Programmable digital computer used to control machinery

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<span class="mw-page-title-main">RS-232</span> Standard for serial communication

In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a DTE such as a computer terminal or PC, and a DCE, such as a modem. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997.

<span class="mw-page-title-main">Digital electronics</span> Electronic circuits that utilize digital signals

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<span class="mw-page-title-main">Universal asynchronous receiver-transmitter</span> Computer hardware device

A universal asynchronous receiver-transmitter 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.

<span class="mw-page-title-main">Data type</span> Attribute of data

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<span class="mw-page-title-main">CAN bus</span> Standard for serial communication between devices without host computer

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<span class="mw-page-title-main">Modbus</span> Serial communications protocol mainly developed for programmable logic controllers

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<span class="mw-page-title-main">LAPB</span>

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<span class="mw-page-title-main">Arithmetic logic unit</span> Combinational digital circuit

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<span class="mw-page-title-main">PlayStation technical specifications</span> Overview of the technical specifications of the PlayStation

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In digital electronics, a level shifter, also called level converter or logic level shifter, or voltage level translator, is a circuit used to translate signals from one logic level or voltage domain to another, allowing compatibility between integrated circuits with different voltage requirements, such as TTL and CMOS. Modern systems use level shifters to bridge domains between processors, logic, sensors, and other circuits. In recent years, the three most common logic levels have been 1.8V, 3.3V, and 5V, though levels above and below these voltages are also used.

References

PD-icon.svg This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22.