Please in your own words describe SPI, I2C, and UART with the following details: (1) What do the abbreviations stand for? (2) How does each of them work? (3) What are the limitations for the number of devices that can be connected for each of them? Solution 1)SPI is Serial Peripheral Interface.I2C (Inter-Integrated Circuit.UART, for Universal Asynchronous Receiver Transmitter. 2)SPI :It includes master and slave or muliple slaves.It has 3 or multiple wires,multiple clock,serial in and out,Master sets clock for slaves.It asks one to listen up by cheap select port and sends command with serial data out port and receives output from slaves through the serial data in port . I2C:Every cheap has address which is useful for calling them.There are two wires SDA and CLK.SDA is bi-directional flow means data can be send and receive at same time.Master sets clock which is useful for communication.Master sends start condition through SDA for slaves to listen for their address.Master sends address of chip and waits for acknoweldgement.After this read and write command is sent. follwed by end command of transmission. UART:It depend on baud rate between transmitter and receiver controller.MCU receives bits into RX port at specific baud rate.There is no mater clock between transmitter and receiver only baud rate.It transfers data as:1 start bit,8 data bits and 1 stop bit.We can have any voltage level.For long distance ,5V is not useful hence 12v is used. 3)Limitations: SPI:1)It needs more wires.2)Master has to control all communications I2C:1)There can be address conflict.2)Due to pull up resistors speed is low. UART:1)There may be difficulties in speed unless both ends have suitable clock.2)Handshaking requires injecting data in stream.