Что (кто) такое stop bit - определение
FORM OF SERIAL COMMUNICATION LACKING SYNCHRONIZATION CONTROL SIGNALS
Asynchronous communications system; Start-stop transmission; Stop bit; Asynchronous serial; Start bit; Asynchronous start-stop; Start-stop signalling; Asynchronous serial protocol
![order of data bits]], the presence or absence of a parity bit, the form of parity (even or odd) and the transmission speed must be pre-agreed by the communicating parties. The "stop bit" is actually a "stop period"; the stop period of the transmitter may be arbitrarily long. It cannot be shorter than a specified amount, usually 1 to 2 bit times. The receiver requires a shorter stop period than the transmitter. At the end of each character, the receiver stops briefly to wait for the next start bit. It is this difference which keeps the transmitter and receiver synchronized.](https://commons.wikimedia.org/wiki/Special:FilePath/Puerto serie Rs232.png?width=200 "order of data bits]], the presence or absence of a parity bit, the form of parity (even or odd) and the transmission speed must be pre-agreed by the communicating parties. The \"stop bit\" is actually a \"stop period\"; the stop period of the transmitter may be arbitrarily long. It cannot be shorter than a specified amount, usually 1 to 2 bit times. The receiver requires a shorter stop period than the transmitter. At the end of each character, the receiver stops briefly to wait for the next start bit. It is this difference which keeps the transmitter and receiver synchronized.")
stop bit
In serial communications, where each bit of the message is
transmitted in sequence, stop bits are extra "1" bits which
follow the data and any parity bit. They mark the end of a
unit of transmission (normally a byte or character).
For example, characters on an EIA-232 serial line may have
one or two stop bits added. Some UARTs even allow for 1.5
stop bits but one is probably the most commonly used. A
serial connection may be described as, for example, "8N1"
which means eight data bits, no parity and one stop bit.
(1995-01-24)
start bit
<protocol> A bit which signals the start of transmission of
a character on a serial line. For an RS-423 signal, the
line is normally at logical zero which there is no data and
the start bit is a logical one. The zero-one transition tells
the receiver when to start sampling the signal to extract the
data bits.
[Is this upside-down? ]
(1995-02-02)
Asynchronous serial communication
Asynchronous serial communication is a form of serial communication in which the communicating endpoints' interfaces are not continuously synchronized by a common clock signal. Instead of a common synchronization signal, the data stream contains synchronization information in form of start and stop signals, before and after each unit of transmission, respectively.
Википедия
Asynchronous serial communication
Asynchronous serial communication is a form of serial communication in which the communicating endpoints' interfaces are not continuously synchronized by a common clock signal. Instead of a common synchronization signal, the data stream contains synchronization information in form of start and stop signals, before and after each unit of transmission, respectively. The start signal prepares the receiver for arrival of data and the stop signal resets its state to enable triggering of a new sequence.
A common kind of start-stop transmission is ASCII over RS-232, for example for use in teletypewriter operation.
