Interfacing methods of microcontroller

Presented By :- Diwaker PantME (REGULAR- 2011)NITTTR CHD

What is Interfacing.

Need of interfacing.

Micro-controller Interfacing – Basics.

Interfacing Methods.

Microcontroller Interfaces Examples.

April 13, 2023 Presented by :- Diwaker Pant 2

Transfer of data between microcontrollers and peripherals (memory, I/O devices etc.) implemented using buses called interfacing.

Connecting the computation capabilities of a microcontroller to external signals or to external world.

Creating man-machine interaction.


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.



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


Wires:◦ Unidirectional ◦ Bi-directional

Bus◦ Set of wires with a

single function. Address bus, Data bus


Microcontroller

Memory(ROM)

Data Bus

AddressBus

Enable

RD/WR

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


Microcontroller(8051)

P0

P2

P1

P3

ALELATCHEnable

PSENROM

OE

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



Advantages


Disadvantages

Simplest interface.

Lowest-cost to implement.

High speed

Low programming overhead

Only on/off control/monitoring

Short distance, few feet maximum.

Single device control/monitoring

Digital Input Digital output

Reading the status of buttons or switches

Keypad Interface

Sensor Interface

Relay control

LED Display

LCD

DAC


Advantages Disadvantages

Simple interface

High speed

Low programming overhead

Not all microcontrollers have analog I/O.

Complicates the circuit design when external ADC /DAC are needed.

Short distance, few feet maximum.April 13, 2023 Presented by :- Diwaker Pant 13


April 13, 2023Presented by :- Diwaker Pant 15




PIC I/O Port


Pin No.

Function

Description

1 Vss Connected to Ground

2 Vcc +5v supply

3 VEE Contrast control Power supply

4 RS 0=Select Command Register1=Select Data Register

5 R/W 1=Read , 0=Write

6 EN Enable

7-14 DB0-DB7

8-bit data bus


PIC16F8XX


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.

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.



PIC

SDASCL

In this system 4 signal wires are used.

1.CS= Chip Select

2.DIN= Data In

3.DOUT= Data Out

4.CLK= Clock Signal


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.



PIC-16F8XXMULTIMEDIA

CARDMMC

CS

DIN

CLK

DOUT


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.


Microcontrollers(Theory and applications)-Ajay V. Deshmukh( Page no.215- 232).

Microcontroller interfacing techniques by BiPOM Electronics, INC (www.bipom.com)

April 13, 2023Presented by :- Diwaker Pant

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Interfacing methods of microcontroller