#QT4.8 QSERIALPORT SERIAL#
#QT4.8 QSERIALPORT CODE#

#QT4.8 QSERIALPORT SERIAL#

For even and odd parity, the serial port will set the parity bit (one bit after the data bit), and use a value to ensure that the transmitted data has even or odd logic high bits. Of course, no check digit is also possible. There are four error detection methods: even, odd, high and low. Parity bit: a simple error detection method in serial communication. The more the number of bits suitable for the stop bit, the greater the tolerance for synchronization of different clocks, but the slower the data transmission rate.Д. Therefore, the stop bit not only indicates the end of the transmission, but also provides an opportunity for the computer to correct clock synchronization. Since the data is timed on the transmission line, and each device has its own clock, it is likely that there is a small out of synchronization between the two devices in the communication. Typical values вЂ‹вЂ‹are 1, 1.5 and 2 digits. Since the actual data bits depend on the choice of the communication protocol, the term 'packet' refers to any communication situation.Д¬, stop bit: used to indicate the last bit of a single packet. Each packet refers to a byte, including start/stop bits, data bits and parity bits. If the data uses simple text (standard ASCII code), then each data packet uses 7-bit data.

#QT4.8 QSERIALPORT CODE#

The extended ASCII code is 0пЅћ255 (8 bits). For example, the standard ASCII code is 0пЅћ127 (7 bits). How to set it depends on the information you want to send. When a computer sends an information packet, the actual data is often not 8-bit. Data bit: This is a parameter to measure the actual data bit in communication. High baud rate is often used for communication between instruments placed very close, a typical example is the communication of GPIB devices.Д«. The baud rate can be much greater than these values, but the baud rate is inversely proportional to the distance. Usually the baud rate of the telephone line is 14400, 2880. Generally, the modulation rate is greater than the baud rate, such as Manchester encoding). Refers to the change of the signal within a unit time after being modulated, that is, the number of carrier parameter changes within a unit time, such as 240 characters per second, and each character format contains 10 bits (1 start bit, 1 Stop bit, 8 data bits), the baud rate at this time is 240Bd, and the bit rate is 10 bits*240/sec=2400bps. For two ports to communicate, these parameters must match.ДЄ, Baud rate: This is a parameter to measure the symbol transmission rate. The most important parameters of serial communication are baud rate, data bits, stop bits and parity. The other lines are used for handshake, but are not required. Since serial communication is asynchronous, the port can send data on one wire while receiving data on the other wire. The communication is completed by using 3 wires, which are ground wire, sending and receiving. Typically, the serial port is used for the transmission of ASCII characters. For example, when IEEE488 defines a parallel traffic state, it stipulates that the total length of the device line shall not exceed 20 meters, and the length between any two devices shall not exceed 2 meters for the serial port, the length can reach 1200 meters. It is very simple and can realize long-distance communication. Although slower than byte-based parallel communication, the serial port can use one wire to send data while using another wire to receive data. The serial port sends and receives bytes bit by bit. The concept of serial communication (Serial Communications) is very simple. Reference example (simple serial port example)

Qt4.8 qserialport