An example of communication between a microcontroller and an accelerometer sensor using the spi interface will be demonstrated in this example. Interintegrated circuit i 2 c npx is a twowired protocol that can operate at different speeds standard mode, fast mode, and highspeed mode. A clock signal named sclk, sent from the bus master to all slaves. It is a protocol intended to allow multiple slave digital integrated circuits chips to communicate with one or more master chips. So for a spi to work, one should be master, and other a slave. The i2c bus physically consists of 2 active wires and a ground connection. The i2c is the short form of interintegrated circuit, is a type of bus, which designed and developed by philips in 1980 for interchip communication.
I2c bus communication protocol tutorial,applications. A web developers guide to communication protocols spi. Serial peripheral interface spi oregon state university. Today, at the low end of the communication protocols we find the interintegrated circuit i2c and the serial peripheral interface spi protocols. Read from one register in a device s a6 a5 a4 a3 a2 a1 a0 0 device slave address7 bits b7 b6 b5 b4 b3 b2 b1 b0 a register address n 8 bits a start ack ack. Like spi, i2c is synchronous, so the output of bits is. Discussion of particular chiptochip communication protocols. An1021601 i2c manual overview description philips semiconductors developed the i2c bus over 20 years ago and has an extensive collection of specific use and general purpose devices.
These protocols helps the main board to communicate with different peripherals by interfacing mechanism. Both protocols are commonly used in electronic devices like smartphones, tvs and laptops to control peripherals like power management chips, input devices. An introduction to i2c, one of the main embedded communications protocols in. In this piece, we will explain what uart and spi are, explain the differences between uart vs spi, discuss some common applications that use uart and spi, and provide you with information to help you get started with debugging and programming embedded systems that use uart or spi. This application note was developed from the 3 hour long i2c overview tecforum presentation at designcon 2003 in san jose, ca on 27 january 2003 and provides a broad overview of how the i2c bus compares to. In this tutorial, you will learn all about the i2c communication protocol, why you would want to use it, and how its. An introduction to i 2 c and spi protocols abstract. Difference between i2c and spi communication protocols speed. An introduction to i2c and spi electronic products. Similar to the i2c protocol, spi and uart also used for the chip to chip communication.
With i2c, you can connect multiple slaves to a single master like spi and you can have multiple masters controlling single, or multiple slaves. Sprugp2amarch 2012 keystone architecture serial peripheral interface spi user guide submit documentation feedback. It is only intended for short distance communications within a single device. With both spi and i2c, one can advance to higher layers if one restricts ones focus to particular styles of chip. An introduction to i2c and spi protocols article in ieee instrumentation and measurement magazine 121. Although other protocols are simpler and do not have speed limitation such as spi. Implementation of the communication protocols spi and i2c. This starts the clock running so the data on miso is brought into the uc.
Both protocols are well suited for communications between integrated circuits for slow communication with onboard peripherals. Without going to the protocols, if you want to expand the peripheral features of the microcontroller, the complexity and power consumption will increase. Spi isnt really a standard so much as a term which is used to describe a wide variety of communications designs. I2ctospi bridge lowcost interface for the qf1da512 and qf1d512 rev a3, may 09. To figure out why one might want to communicate over i2c, you must first compare it to the other available options to see how it differs.
Difference between i2c and spi communication protocols. There is a lot of serial communication protocol but in which i2c and spi are very famous, in this article, i will discuss the difference between i2c and spi i2c vs spi. First, well begin with some basic concepts about electronic communication, then explain in detail how spi works. The serial peripheral interface spi is a synchronous serial communication interface specification used for shortdistance communication, primarily in embedded systems. Serial peripheral interface spi 19 synchronous fullduplex communication. Introducing i2c the name i2c is shorthand for standard interintegrated circuit bus i2c is a serial data protocol which operates with a masterslave relationship i2c only uses two physical wires, this means that data only travels in one direction at a time.
A web developers guide to communication protocols spi, i2c, uart, gpio. An introduction to i2c and spi protocols researchgate. Communication between integrated circuits, cards and devices is a problem as. An introduction to shift registers and potential uses. I am pretty new and want to know the basic operation of the communication protocols such as i2c, uart, spi. An i2c protocol is one of the serial communication protocol that is used for the chip to chip communication. Spcr bit rate, cpol, cpha, ms spdr transfer data to and from spi shift register 39 conclusions, spi and i2c ii2c and spi are highly used for communicationc and spi are highly used for communication with peripherals like serial eeproms, clocks, etc. I2c i2c overviewoverview l i2c is a bidirectional protocol l data is sent either direction on the serial data line sda by the master or slave. Today, at the low end of the communication protocols we find the interintegrated circuit i 2 c and the serial peripheral interface spi protocols.
Serial peripheral interface spi for keystone devices. Protocol is a protocol intended to allow multiple slave or. Ive used various flavors of avr microcontrollers, writing to them in assembly, c, and arduino wiringprocessing. Communication protocols like uart, spi, i2c play an very important role in microcontrolled based embedded systems development. Chapter 1introduction the spi allows software to program the following options. It seems the serial peripheral protocol spi was first introduced with the first microcontroller. This document discusses i2c and spi, their history, summarizes their features, and. Universal serial bus battery charger market global scenario, market size, outlook, trend and forecast, 2015 2024 universal serial bus also known as usb were introduced in 1990s it defines cables, connectors, and communication protocol used in bus for connection, communication, and power supplies between computers and other electronic devices. I2c and spi are both bus protocols that allow shortdistance, serial data transfer.
Introduction i2c and spi serial communication protocols meant for short distances inside the box low complexity low cost low speed a few mbps at the fastest to be discussed. The serial peripheral interface spi is one of the widely accepted. Introduction serial peripheral interface spi is an interface bus commonly used to send data between microcontrollers and small peripherals such as shift registers, sensors, and sd cards. So basically there will be two main pins on each side, lets say x and y. In this series of articles, we will discuss the basics of the three most common protocols. I2c bus protocol tutorial, interface with applications nowadays the protocols play an essential role in the embedded system design. Technical article introduction to the i2c bus december 16, 2015 by robert keim this article covers the essential characteristics and prominent advantages of the interintegrated circuit aka i2c serialcommunications protocol. An introduction to i 2 c and spi protocols ieee journals. If no peripherals are selected, the outgoing data will be ignored. Keystone architecture serial peripheral interface spi user guide. C interintegrated circuit, pronounced isquaredc, is a synchronous, multi master. Difference between i2c and spi i2c vs spi, you should. Data can flow in any direction on the i2c bus, but when it flows is controlled by the master device.
Same sensing technique you are using in lab an electric field pretouch system for grasping and comanipulation, icra2010. Serial peripheral interface spi, interintegrated circuit i2c, and universal asynchronous receivertransmitter uart driven communication. I2c bus communication protocol tutorial,applications microcontrollers lab july 31, 2015 electronics tutorials leave a comment data transmission can mainly occur in two ways, parallel or serial. To get the spi clock to run, a dummy write is made to the spi spdr register. Introduction this paper discusses three popular serial buses. Spiclk frequency spi module clock2 through spi module clock256 3. Improved serial communication technology allows for transfer at higher speeds and is dominating the modern digital technology. Serial communications many fewer lines are required to transmit data. Serial peripheral interface spi 19 synchronous fullduplex communication can have multiple slave secondary devices. Com, i2c, spi, and ethercat in action cse 466 communication 22.
Additionally, the versatile i2cbus is used in various control architectures such as. Cant share communication lines, slower than spi and i2c. I2c originates from the philips semiconductor devision, while spi was created by motorola. Every device hooked up to the bus has its own unique address, no matter whether it is an mcu, lcd driver, memory, or asic. Both are synchronous protocols, appropriate for short distance communications, and they generally operate in the 3. Basics of the i2c communication protocol circuit basics. An introduction to i2c and spi protocols semantic scholar. As such, it barely even qualifies as a physical layer protocol. Interintegrated circuit, abbreviated as i2c is a serial bus short distance protocol developed by philips semiconductor about two decades ago to enhance communication between the core on the board and various other ics involved around the core. Serial communication sending data one bit at one time, sequentially serial vs parallel communication cable cost or pcb space, synchronization, distance.
Sda is the serial data line, and scl is the serial clock line. What is the difference between spi vs uart protocol. Serial peripheral interface spi is an interface bus commonly used to send. The i2c is a twowire bus used to enable communication between two or more devices that are normally on the same board. I2c and spi are both bus protocol to allow the user for shortdistance, serial data transfer. Typical applications include secure digital cards and liquid crystal displays.
I wanted to know that what makes spi faster than i2c. Both protocols are well suited for communications between integrated circuits and for. I2ctospi bridge lowcost interface for the qf1da512 and. Serial protocols will often send the least significant bits first, so the smallest bit is on the far left. If i am not wrong using i2c we can go used 400kbps while in spi we can achieve 10mbps also. Spi and i2c were both conceived in the 1980sspi by motorola and i2c by philips now nxp.
I2c contain two buses sda and scl and it require a less pins. A typical electronic product today will have one or more serial buses in them. History when connecting multiple devices to a microcontroller, the address and data lines of each device were conventionally connected individually. Today, at the low end of the communication protocols, we find i. C for interintegrated circuit, protocol and spi for serial peripheral interface. Both protocols are wellsuited for communications between integrated circuits, for slow communication with onboard peripherals. I is a bidirectional protocol i2c is a bidirectional protocol.