UART is typically for a point to point connection, I2C is a bus protocol. UART is not a protocol (see also remark of Justme below), I2C is a protocol. UART is (can be) full duplex, I2C is not. UART does not have a master/slave principle (no protocol), I2C has..
Keeping this in view, when UART is preferred over i2c and SPI?
Do keep in mind that the device you are using must support the communication peripheral as well.
| UART | SPI |
| Complexity | Simple | Complex as device increases |
| Speed | Slowest | Fastest |
| Number of devices | Up to 2 devices | Many, but there are practical limits and may get complicated |
| Number of wires | 1 | 4 |
Furthermore, which is better to use i2c or SPI? SPI supports higher speed full-duplex communication while I2C is slower. I2C is cheaper to implement than the SPI communication protocol. SPI only supports one master device on the bus while I2C supports multiple master devices. I2C is less susceptible to noise than SPI.
Then, which is faster i2c or UART?
UART - simple; not high speed; no clock needed; limited to one device connected to the Pi. I2C - faster than UART, but not as fast as SPI; easier to chain many devices; RPi drives the clock so no sync issues.
What are SPI and i2c?
Introduction. I2C and SPI are both bus protocols that allow short-distance, serial data transfer. Both protocols are commonly used in electronic devices like smartphones, TV's and laptops to control peripherals like power management chips, input devices and DACs.
Related Question Answers
Is UART a protocol?
UART stands for Universal Asynchronous Receiver/Transmitter. It's not a communication protocol like SPI and I2C, but a physical circuit in a microcontroller, or a stand-alone IC. A UART's main purpose is to transmit and receive serial data.Is i2c a UART?
UART is not a protocol (see also remark of Justme below), I2C is a protocol. UART is (can be) full duplex, I2C is not. UART does not have a master/slave principle (no protocol), I2C has. UART can be used for transmission over distance, I2C is not meant for that.Is UART full duplex?
full duplex means we can transmit and receive data at the same time. though having two channels, it is not completely full duplex system. but if u observe then in PIC or AVR, they have provided different buffers also for transmission and reception. therefore in that case, uart becomes full duplex system.How does a UART work?
The universal asynchronous receiver-transmitter (UART) takes bytes of data and transmits the individual bits in a sequential fashion. At the destination, a second UART re-assembles the bits into complete bytes.What is i2c used for?
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems. It was invented by Philips and now it is used by almost all major IC manufacturers.Is i2c faster than serial?
I2C communication So based on this information I've concluded that the fastest common bit rate used for the serial communication is 115200 bits/s. This seems to be significantly lesser than the bit rates for I2C, which appear to start at 100 kbit/s which equates to 100000 bits/s.Which protocol is used in Arduino?
UART
What is UART TTL?
UART = Universal Asynchronous Receiver/Transmitter. It is the basic chip (or virtual function in a microcontroller) which encodes the data bits serially into a standard format with a start bit, stop bit(s), speed, etc. A TTL UART will output (and input) only TTL levels, essentially 0 bit = 0V and 1 bit = 5V.Can vs UART?
UART: It is universally asynchronous receiver ad transmitter used for sending and receiving data asynchronously i.e. you don't have to wait for acknowledging of first bit, CAN: It is Controller Area Network which the name itself implies that device which controls the network area to transfer data without any host.Why UART is called asynchronous?
Pronounced u-art, and short for universal asynchronous receiver-transmitter, the UART is a computer component that handles asynchronous serial communication. Every computer contains a UART to manage the serial ports, and some internal modems have their own UART.What is UART interface?
A UART (Universal Asynchronous Receiver/Transmitter) is the microchip with programming that controls a computer's interface to its attached serial devices. Converts the bytes it receives from the computer along parallel circuits into a single serial bit stream for outbound transmission.What is i2c communication?
I2C is a serial communication protocol, so data is transferred bit by bit along a single wire (the SDA line). Like SPI, I2C is synchronous, so the output of bits is synchronized to the sampling of bits by a clock signal shared between the master and the slave.What is meant by serial communication?
In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.What is the speed of SPI protocol?
The SPI bus, which operates at full duplex (means, signals carrying data can go in both directions simultaneously), is a synchronous type data link setup with a Master / Slave interface and can support up to 1 megabaud or 10Mbps of speed. Both single-master and multi-master protocols are possible in SPI.What is the speed of i2c bus?
I2C defines several speed grades but the term baud rate is quite unusual in this context. The speed grades (standard mode: 100 kbit/s, full speed: 400 kbit/s, fast mode: 1 mbit/s, high speed: 3,2 Mbit/s) are maximum ratings.What is Raspberry Pi i2c?
I2C is a multi-device bus used to connect low-speed peripherals to computers and embedded systems. The Raspberry Pi supports this interface on its GPIO header and it is a great way to connect sensors and devices. Once configured you can connect more than one device without using up additional pins on the header.What is baud rate in serial communication?
The baud rate is the rate at which information is transferred in a communication channel. In the serial port context, "9600 baud" means that the serial port is capable of transferring a maximum of 9600 bits per second.What is the maximum distance of the i2c bus?
So the maximum bus length of an I2C link is about 1 meter at 100 Kbaud, or 10 meters at 10 Kbaud. Unshielded cable typically has much less capacitance, but should only be used within an otherwise shielded enclosure.How many devices can be connected to i2c?
I2C Device Addressing All of our modules and the common chips you will use will have 7 bit addresses. This means that you can have up to 128 devices on the I2C bus, since a 7bit number can be from 0 to 127. When sending out the 7 bit address, we still always send 8 bits. 
