Definitions of Serial TTL UART MCU acronyms

Question

I was looking for a comprehensive list of terms and acronyms concerning serial peripheral communication including their descriptions and, crucially, how they relate to each other. Since this site often comes up in searches for individual terms I thought it might be useful to collect all these terms in one place.

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Answer 1

serial - The sending of data in sequential bits

peripheral - A device connected to a computer system but not part of its core components

bitbang - A method of implementing peripheral communication through software as opposed to dedicated hardware for generating and processing data signals

DB-9 - Also DE-9, it is a 9-pin version of the early DB-25 style of physical connector consisting of 9 pins arranged in 2 rows commonly used for interfacing peripherals over the RS-232 serial data communication interface

COM - Communication port The name of an addressable serial port interface originated by IBM using the DB-9 connector

RS-232 - Recommended Standard #232 Also known as EIA/TIA-232, this is an interface standard for serial data communication

RS-485 - Recommended Standard #485 Also known as EIA/TIA-485(-A) is an interface standard for balanced-pair serial data communication

FTDI - Future Technology Devices International Limited This is a Scottish semiconductor company which produces a very popular USB-to-Serial adapter IC (integrated circuit)

FT232RL - The part number of an IC produced by FTDI commonly found in TTL Serial adapters

TTL - Transistor-Transistor Logic Denotes signal voltages at the transistor logic-level of 3v to 5v

MCU - Microcontroller unit Also MC, UC, or μC, it is a single IC chip with complex, computer-like functionality

UART - Universal Asynchronous Receiver/Transmitter Is a simple protocol for exchanging serial data utilizing between 2 to 9 data signals

USB - Universal Serial Bus A modern serial data communication standard that is extendable, auto-configurable, and highly complex

RX - Receive Is the signal pin used for receiving serial data at an implied TTL voltage

TX - Transmit Is the signal pin used for sending serial data at an implied TTL voltage

RXD - Receive Data Is a signal pin (#2 on DB9) used for incoming serial data per the RS232 standard

TXD - Transmit Data Is a signal pin (#3 on DB9) used for outgoing serial data per the RS232 standard

DTR - Data Terminal Ready Is a signal pin (#4 on DB9) used for an optional flow control mechanism of the RS232 standard

GND - Ground Is a voltage reference pin (#5 on DB9) used for signal ground

DSR - Data Set Ready Is a signal pin (#6 on DB9) used for an optional flow control mechanism of the RS232 standard

RTS - Request to Send Is a signal pin (#7 on DB9) used for an optional flow control mechanism of the RS232 standard

CTS - Clear to Send Is a signal pin (#8 on DB9) used for an optional flow control mechanism of the RS232 standard

TXL - Transmit LED Is a status pin capable of driving an LED to indicate transmit activity on the COM port

RXL - Receive LED Is a status pin capable of driving an LED to indicate receive activity on the COM port

VCC - Voltage Common Collector Is a power-carrying connection with a higher voltage relative to GND

VSS - Voltage Source Supply Same as GND

SPI - *Serial Peripheral Interface is a synchronous serial communication interface well suited for short distances

I2C - Inter-Integrated Circuit Also IIC or I²C, it is a serial communications bus well suited for short distance peripheral-microcontroller communication

TWI - Two-Wire Interface Alternative name for I2C

VCP - Virtual COM Port A component of modern USB-to-Serial adapter drivers that allows the operating system to present a legacy COM port to applications that expect or require it for serial communication