They are both bidirectional and open-collector. Secure Digital cards and liquid crystal displays (LCDs) are common applications. It is as I2C uses an address system and a shared bus = many different devices can be connected using the same wires and all data are transmitted on a single wire and have a low pin count. I2C is a two-wire serial protocol for connecting low-speed devices such as microcontrollers, EEPROMs, Analog to Digital (A/D) and Digital to Analog (D/A) converters, Input/Output (I/O) interfaces and other similar peripherals in an … A number of bits can be sent or received in a continuous stream. Slaves read bits when received. Serial Peripheral Interface (SPI) is a master-slave style protocol that has a single master and multiple slave architecture. Technology Introduction: Communications Protocols SPI, I2C, I2S. why the SPI can archieve much higher data rate compared to I2C ? Still, this implementation would require one SS line per slave. The most notable difference right off the bat is that, while you can use multiples masters and slaves with I2C, SPI allows a single master device with a maximum of four slave devices. SPI is more susceptible to noise than I2C. 1. When the bus is idle, both the lines should be on high power. I2C and SPI are both bus protocols that enable the user to transfer serial, short-distance data. Save my name, email, and website in this browser for the next time I comment. Let’s try to figure this out in this post and try to answer all these questions. Comparing to the SPI, the data transfer speed of I2C is limited to a few Mhz. What's fundamentally different about SPI is that it is synchronous.As opposed to, say, RS-232, an asynchronous signaling standard.. An important property of asynchronous signaling is the baudrate, the frequency at which the bits in a byte are sent. Both I2C (Inter-Integrated-Circuit) & SPI (Serial-Peripheral-Interface) are serial & synchronous protocol and used for the applications where communication speed is not a big concern and a simple & low-cost communication mechanism is required in a network of devices such as microcontrollers, sensors, and memory. Search titles only. Share this post: It is also called as I2C. If an appropriate response is required then the slave gives the master data one bit at a time along the MISO line by sending LSB bit first. Which one is better, I2C or SPI? Difference between I2C and SPI ( I2C vs SPI ), Introduction to I2C & SPI Communication Protocol, Selecting Between I2C and SPI for Your Project, SPI vs I2C Protocol Differences and Things to Consider, UART Communication Protocol - How it works? For a given application, how to decide which one will be the better option? only 2 wires for communication. Like human beings, communication protocols allow data transmission between hardware, software or a combination of the two with different languages. It may become complex with increasing numbers of devices. Mainly because SPI can be run much much faster -- up to many 10's of MHz in some cases. – Jot Nov 2 '17 at 1:18 That is the most significant advantage of SPI. First find out what you need, than search the best protocol and hardware peripheral (UART, I2C, SPI, GPIO) for it. Its primary purpose was to provide a convenient way to connect a CPU to peripheral chips on a TV set. The master then selects the desired slave for communication by switching the slave peripheral (SS) selection chip to a “low” state and activating the specific slave whom the master wants to communicate by using the slave selection (SS). 2. Since there is only one line (SDA) for transmission and reception of data in I2C, it supports half-duplex communication. on Facebook As far as the Physical Structure is concerned, I2c requires only 2 wires Serial Data line (SDA) and a Clock line (SCL). Master in, slave out (MISO)The device that generates the clock signal is called the master. Once the clock of the device goes low it will keep the SCL line in low state until it reaches the clock’s high level. So based on our discussion so far it quite clear that I2C is suitable for the applications where per transaction, a small amount of data needs to be transferred and the network must have multiple master nodes. on Google+. The communication is started by the master always. This is not possible in the case of SPI. To explain it better let’s categorize the difference in 6 main points and then we will discuss each of them in details:-. By: Search Advanced search … Menu. Today, however, I2C is used in a wide range of communication applications, from LCD to Factory Automation. These lines are pulled up to supply voltage with the help of pull-up resistors as shown in the below image. Some unofficial SPI variants only need 3 wires, that is a SCLK, SS and a bi-directional MISO/MOSI line. The main difference is, that addressing a device is part of the I2C protocoll, whereas you might need additional chip select lines for SPI! SPI devices use push-pull drivers that offer superior speed and signal integrity when compared to the open drain lines employed in the I2C protocol. Likewise, when CPOL is Up, SCK is HIGH in idle state and LOW in the active state. For example, in STM32F4xx, if the peripheral clock of 40MHz then in I2C data rate is 400Kbps and an SPI data rate is 20Mbps. Three additional modes were also added later: fast mode plus-1MHz; high-speed mode, 3.4MHz; and ultra-fast mode, 5MHz. But I'll assume that you are talking about traditional serial communication standards. What is I2C Protocol? but it s a constrain. Serial Clock (or SCL) and Serial Data (or SDA) are the two wires or lines. I2C stands for “inter-Integrated Circuit bus”. SPI, I2C, I2S. SPI uses 2 separate data lines for transmission (MOSI – Master transmitter) and reception (MISO – Master receiver) of data, it supports full-duplex communication. I2C vs SPI Protocol Analyzers: Differences and Similarities.