The document discusses various interfacing techniques with the 8051 microcontroller, including LCD, external ROM, RAM, ADC, and DAC integration. It explains serial communication protocols such as USART, UART, SPI, and USB, highlighting their functions, advantages, and limitations. Additionally, it outlines how the SPI protocol facilitates communication between a master and multiple slave devices using specific data lines and control registers.

1. 8051 Interfacing

3. LCD INTERFACING TO 8051

5. EXTERNAL ROM INTERFACING TO 8051

6. EXTERNAL ROM INTERFACING TO 8O51

8. EXTERNAL RAM INTERFACING TO 8051

9. ADC

10. ADC

11. DAC

14. USART
• USART stands for Universal
Synchronous Asynchronous Receiver
Transmitter. It is sometimes called
the Serial Communications Interface
or SCI. Synchronous operation uses
a clock and data line while there is
no separate clock accompanying the
data for Asynchronous transmission.

15. UART
• UART stands for universal
asynchronous receiver / transmitter
and defines a protocol, or set of
rules, for exchanging serial data
between two devices. UART is very
simple and only uses two wires
between transmitter and receiver to
transmit and receive in both
directions. Both ends also have a
ground connection.

16. UART:- Universal Asynchronous Receiver / Transmitter
Here only two devices can communicate using this
protocol at once

17. TYPES OF SERIAL COMMUNICATION PROTOCOLS
SPI-SERIAL PERIPHERAL INTERFACE

18. SPI
master-Device which provides clock for communication
slave-which utilizes master clock for communication
• Two data lines (MISO,MOSI)
• MOSI-master sends data to its slaves
• MIS0-slave responds to master
• One serial clock line (SCK)-clock
provided by master
• One slave select (SS)-line used to
select slave to which master wants to
communicate

19. SPI
• Master sends the data via MOSI while
Slave responds via MISO Line
• SS is used to make particular slave
awake with who master wants to
communicate
• Registers used to implement SPI
communication –SPDR,SPSR,SPCR
• SPDR-SPI DATA REGISTER
• SPSR-SPI STATUS REGISTER
• SPCR- SPI CONTROL REGISTER

20. SPI
• Advantages:
• Multiple slaves connected to single
master
• Faster form of serial communication
• Disadvantages:
• Requires multiple slave select wires
for connecting multiple slaves
• No two slave can communicate with
each other directly

21. USB
• Universal Serial Bus (USB) is
technology that allows a person to
connect an electronic device to a
computer. It is a fast serial bus type.
A USB Type A plug. It is mostly used
on personal computers. USB is also
used on other devices, such as
smartphones and video game
consoles.

22. USB

23. I2C-INTER INTEGRATED CIRCUIT

24. I2C