Please everyone a great god help me, under the title four difference, thank you thank you; The more detailed, the better
CodePudding user response:
To find the information in detail, you should see their, Probably is this: SPI (Serial Peripheral Interface) : a typical 4 wire full-duplex synchronous communication protocols, data input, data output, clock, slice selection, are three inside one of the fastest communication bus and Peripheral expansion needs through the CS, seemingly not the quantity, I2C (Intel - IntegratedCircuit) : two wire two-way communication bus, synchronous communication, the bi-directional data and clock lines, the highest frequency of 400 k, can hang equipment 128, UART is two wire two-way communication bus, RX, TX2 line, asynchronous communication, the baud rate for communication through agreement, to require high baud rate error and bit error rate is the tallest of three, just point to point communication bus theory, through the upper protocol extensions, can hang multiple devices, due to standard out early, so the current control device, one of the most widely used protocol by level transformation extensions, becomes 485 fieldbus, and traditionally one of the most used industrial field bus,
CodePudding user response:
SPI and I2C (IIC) is a synchronous transmission protocol, the character is: the equipment is the host (master) and distinguish from the machine (slave); Host in the communications when sending the clock signal,
The signal of SPI: CS: choose from machine piece of signals, the host will be in the selected from machine communications, effective, low level in more than from the machine system, the host control more than CS signal lines, each connected to a machine, SCK: a serial clock line, from the host connected to each from machine, MOSI: master from into the cable, cable on SPI, data is a one-way, so need to two signal lines, MISO: master into from a cable, In the SPI system, there is only one host, if the host to find any CS line at work by other equipment down, will report a systematic error, and exit the operation,
The characteristics of I2C and signal: I2C can also be more from the system, it is through the address information to choose from the machine, so it went to the selected line, I2C allowed to have multiple host in the same system, he through a set of arbitration agreement to solve the conflicts of the host in a system, allows the device to the host and role, from machine transform SCL: clock signal, SDA: data signal lines,
I2C through complex protocol reduces the connecting cables, and allow more master from, but its price is low transmission speed, I2C defined transport pattern: * standard mode: the highest 100 kbit/s, the bidirectional; * quick mode: the highest 400 kbit/s, bidirectional, compatible with the standard mode; * quick mode Plus: the highest 1 mbit/s, bidirectional, compatible with the first two models; * super fast mode: top 5 mbit/s, one-way (host send only), incompatible, does not support more than god,
In the practical use, mainly is the standard mode and quick mode,
UART is a kind of asynchronous serial communication protocol, it by the local clock and precise timing sampling or switching signal level, UART transceiver of both sides is one to one, and no master-slave, neither side can send data at any time, UART both sides must use same predetermined "baud rate" (time) to communications, at present there are also some fixed signal receiver based on the test to determine the baud rate of technology, but is not widely used, UART signal: RXD: receiving signal lines TXD: send signal lines
People on both sides of the communication is the second line of cross docking,
USART is the extension of UART, it besides support asynchronous transmission, also support synchronous transmission, but the less application,
