1. Presented By :-
Diwaker Pant
ME (REGULAR- 2011)
NITTTR CHD

2.  What is Interfacing.
 Need of interfacing.
 Micro-controller Interfacing – Basics.
 Interfacing Methods.
 Microcontroller Interfaces Examples.
October 9, 2012 Presented by :- Diwaker Pant 2

3.  Transfer of data between microcontrollers and
peripherals (memory, I/O devices etc.) implemented
using buses called inte rfacing .
 Connecting the computation capabilities of a
microcontroller to external signals or to external world.
 Creating man-machine interaction.
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4. The basic need is to have some input/output
peripherals and man-machine interface.
Interactions with a computer or TV are possible
using the mouse /keyboard/display screen.
The no. of real world devices and systems like
mobile phone and washing m/c need the keypad and
display to enable human-computer interactions.
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6.  Address bus for example (A15-A0).
 Data bus for example (D7-D0).
 Control lines : For example in 8051 microcontroller.
 EA (External Access).
 ALE (Address Latch Enable).
 PSEN (Program Store Enable). RD, WR
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7.  Wires: RD/WR
◦ Unidirectional Data Bus
◦ Bi-directional
 Bus
Microcontroller Memory
◦ Set of wires with a Enable
(ROM)
single function.
 Address bus,
 Data bus
Address
Bus
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8. P0
P1
LATCH
ALE Enable
Microcontroller
(8051)
PSEN OE
P3 ROM
P2
 Connects bus to microcontroller or memory
 Often referred to as a pin
◦ Actual pins on periphery of IC package that plug into socket
on printed-circuit board
◦ Today, metal “ pads” connecting processors and memories
within single IC
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9.  Micro-controllers are useful to the extent that they
communicate with other devices, such as sensors ,
motors, switches, keypads , displays memory and even
other micro-controllers.
 To solve the complex problem of balancing circuit
design criteria such as
• Features , Cost , Size , Weight
• Power consumption , Reliability , Manufacturability
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11. Advantages Disadvantages
Simplest interface. Only on/off
control/monitoring
Lowest-cost to implement.
Short distance, few feet
High speed maximum.
Low programming Single device
overhead control/monitoring
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12. Digital Input Digital output
 Reading the status of  Relay control
buttons or switches
 LED Display
 Keypad Interface
 LCD
 Sensor Interface  DAC
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13. Advantages Disadvantages
 Simple interface  Not all microcontrollers
have analog I/O.
 High speed
 Complicates the circuit
design when external
 Low programming
ADC /DAC are needed.
overhead
 Short distance, few feet
maximum.
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18. PIC I/O
Port
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19. P No. F
in unction Description
1 Vss Connected to Ground
2 Vcc +5v supply
3 VEE Contrast control Power supply
4 RS 0=Select Command Register
1=Select Data Register
5 R/W 1=Read , 0=Write
6 EN Enable
7-14 DB0-DB7 8-bit data bus
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20. PIC
16F8XX
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21.  Serial Bus system is divided in two categories.
1. I2C (Inter Integrated Circuit Bus).
2. SPI (Serial Peripheral Interface Bus).
 I2C is 2 wire, one master multiple slaves system.
 SPI is 4 wire , one master multiple slaves system.
Presented by :- Diwaker Pant October 9, 2012 21

22.  In this system two signal (wire) are there namely
 SDA= Serial Data wire.
 SCL= Serial Clock wire.
 To start the communications, the bus master
(typically a microcontroller) places the address of the
device with which it intends to communicate (the
slave) on the bus. All slave devices monitor the bus to
determine if the master device is sending their
address. Only the device with the correct address
communicates with the master.
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23. SDA
SCL
PIC
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24.  In this system 4 signal wires are used.
1.CS= Chip Select
2.DIN= Data In
3.DOUT= Data Out
4.CLK= Clock Signal
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25.  SPI bus is a master/slave interface.
 Whenever two devices communicate, one is referred
to as the "master" and the other as the "slave" device.
 The master drives the serial clock.
 SPI is full duplex: Data is simultaneously transmitted
and received.
Presented by :- Diwaker Pant October 9, 2012 25

26. CS
DIN
MULTIMEDIA
PIC-16F8XX CARD
DOUT MMC
CLK
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28.  We can say that by the help of suitable interfacing
methods we can create Man-Machine interaction.
 Nowadays all automatic systems uses embedded
system and by the help of interfacing we can enjoy the
technology and can make the technology more user
friendly.
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29.  Microcontrollers(Theory and applications)-Ajay V.
Deshmukh( Page no.215- 232).
 Microcontroller interfacing techniques by BiPOM
Electronics, INC (www.bipom.com)
Presented by :- Diwaker Pant
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30. ?
Query
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