The document presents a seminar on electronic communication protocols including SPI, I2C, and UART, focusing on their roles in embedded systems for data exchange. It outlines the types of communication, their advantages and disadvantages, and specifics of each protocol, such as pin configurations and synchronization methods. The seminar highlights the importance of understanding these protocols for practical applications in real-world devices.

1. ELECTRONIC COMMUNICATION
PROTOCOLS
09EC6656 – HIGH SPEED DIGITAL DESIGN
Seminar on
Theoretical Aspects
Prepared & Presented by:
HARIHARAN K
UCC18ECED08,M.Tech Scholar
Dept. of Electronics DesignTechnology,
NIELIT – Calicut.
Guided by:
JAYARAJ U KIDAV
Scientist/Engineer - ‘D’
NIELIT – Calicut.

2. OUTLINE
 Introduction
 Why we need Protocol?
 SPI, I2C
 UART
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3. INTRODUCTION
 Embedded System :
◦ HARDWARE + SOFTWARE to perform a desired application.
 SYSTEM takes INPUT, processes the same, provides
the desired OUTPUT
 COMMUNICATION is happening!
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4. - Examples: CAN, I2C, I2S, SPI, Serial, USART,
UART, USB, RS-232, RS-485, Bluetooth,Wi-Fi,
ZigBee, LIN, MQTT, RFID, NFC etc.,
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COMMUNICATION PROTOCOL
- A set of rules and regulations that allow
two electronic devices to connect to exchange
the data with one and another.
- RealWorld Applications:
- Remote Controlled Gadgets
- FileTransfer between PC and Mobile

5. CATEGORIES
 In terms of communication:
- Serial Communication
- Parallel Communication
 In terms of Peripheral Accessibility:
- Inter System Protocol
Ex: Between a CPU and a Embedded Development board :
USB, UART etc.,
- Intra System Protocol
Ex: Between two devices in a circuit board : SPI, I2C etc.,
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6. SERIAL vs. PARALLEL
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7. Contd.,
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8. Internals of Serial Comm.
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Serial Communication is all about Shift Registers!
Shift registers:
Some D-Flip-Flops serially connected while sharing the same
clock line.

9. How data is sent serially?
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Transmitter: loading data in
parallel to a shift register, and
shifting it out a bit at a time -
Parallel In Serial Out Shift
Register
Receiver: receiving data a single bit at
a time and when all bits are received,
the shift register can be read in
parallel - Serial In Parallel Out Shift
Register

10. SERIAL IO
 Serial communication is preferred,
because:
 Few number of wires, less space etc.,
 Cost effective for long distances
 No Crosstalk and Clock Skew effects
 SerialTransmission Modes:
 Synchronous Data Transfer
 Asynchronous DataTransfer
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11. Synchronous Data Transfer
 Generates the Data Clock and sends it to the receiver which
works accordingly in a synchronized manner.
 Faster and Reliable Mechanism
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12. Asynchronous Data Transfer
 Generates the data clock internally and no incoming serial clock
signal.
 Proper Communication:TX and RX must be using the same baud
rate - rate at which bits are being sent bps (bits per second).
 Uses Start Bit, Stop Bit and Parity Bit for data reliability.
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13. TERMINOLOGIES
 MSB/LSB : Sounds familiar, but it’s crucial!
◦ Asynchronous : LSB sent First
◦ Synchronous : MSB sent First
 SIMPLEX - HALF DUPLEX - FULL DUPLEX
 BAUDRATE - Number of symbols (group of bits)
transceived per second.
-TX and RX should obey same baud rate value!
 MASTER/SLAVE Concept: Usually Synchronous.Sometimes, Multi
Master/Slave too!
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14. SPI
 Serial Peripheral Interface by Motorola in mid-1980’s
 Intra System - Full Duplex, Sync. Serial Communication
Protocol
 4 Pins - 4 wire communication protocol
SCK - Serial Clock
MOSI - Master Out, Slave In
MISO - Master In, Slave Out
CS/SS - Chip Select/Slave Select
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15. SPI - Two key terms
 CPOL - Clock Polarity
 CPHASE - Clock Phase
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16. SPI - Two key terms
 CPOL - Clock Polarity
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17. SPI - Two key terms
 CPHASE - Clock Phase
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18. Contd.,
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19. SPI CONFIGURATIONS
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20. Contd.,
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21. Contd.,
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22. Problem under Multi Slave
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23. Advantages & Disadvantages
 Advantages:
◦ High Speed Protocol & Full Duplex
Communication
◦ No complexity - Address of the Slave Device
◦ Best Suited for Single Master Single Slave
Configuration
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24. Advantages & Disadvantages
 Disadvantages:
◦ Pin Count is directly proportional to the
Number of Slave Devices
◦ No Acknowledgement!
◦ Slow speed device determining the speed
Example Devices: LM74 and TMP125
Temperature Sensors with SPI Interface
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25. I2C
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 Inter Integrated Circuits by Philips in mid-1980’s
 Intra System - Half Duplex Sync. Serial Communication
Protocol
 2 Pins - 2 wire topology
SCK - Serial Clock
SDA - Serial Data

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I2C

27. I2C - Data Format
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- Register Address + Data

28. I2C - Advanced Logics
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29. Advantages:
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30. Disadvantages:
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31. I2C Real World Devices:
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32. I2C vs SPI:
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33. UART
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Inter System - Async. Serial Communication Protocol

34. UART - Connection
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35. UART - Frame
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36. Advantages
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37. Disadvantages
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38. USB vs UART vs USART
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39. REFERENCES
 “Serial I-O”, Dinesh K. Sharma Electrical Engineering
Department I.I.T. Bombay Mumbai 400 076, (version July 11,
2016)
 https://deepbluembedded.com/uart-pic-microcontroller-
tutorial/
 https://i2c.info/
 https://www.slideshare.net/EmertxeSlides/communication-
protocols-31945098
More References are available in Google andYouTube! Practical
experiments are needed to understand the concepts clearly!
Just search these keywords 
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40. THANKYOU!
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