This document provides an overview of embedded systems and input/output interfacing. It discusses ports and port types, peripheral devices like LEDs and seven-segment displays, and output devices such as LCD screens and printers. The document uses examples from microcontrollers like PIC18F458 to explain how ports are used for interfacing and I/O applications in embedded systems.

1. EMBEDDED
PRESENTATION
Prepared by :-
Rahul sharma (11ece29)
Nitin (11ece25)
Piyush gupta (11ece27)
Priya (11ece28)
Incharge:_
Mr. Naresh Tanwar
ECE department
A.C.E.M

2. contents
1.Embedded system
2.Port
3.Port types
4.Peripheral devices
5.Interfacing
6.Output devices

3. Embedded system
 embedded system means processor is
embedded into that
application.
 We can say that it is a computing device
that does a ‘specific focused job’.
examples:air conditioner,VCD player,DVD
player,printer,fax machine,mobile phones.

4. port
 A port is a device
 to receive the bytes from external
peripheral(s) [or device(s) or processor(s)
or controllers] for reading them later using
instructions executed on the processor or
 to send the bytes to external peripheral or
device or processor using instructions
executed on processor

5. example
 SI serial interface in 8051
 SPI serial peripheral interface in 68HC11
 PPI parallel peripheral interface 8255
 Ports P0, P1, P2 and P3 in 8051 or PA, PB,
PC and PD in 68HC11
 COM1 and COM2 ports in an IBM PC

6. I/O port types
1.Serial input output ports
2.Parallel input output ports

7. Serial I/O ports
 Synchronous Serial Input
 Synchronous Serial Output
 Asynchronous Serial UART input
 Asynchronous Serial UART output
 Both as input and as output, for example,
modem.

8. Parallel I/O ports
 Parallel port one bit Input
 Parallel one bit output
 Parallel Port multi-bit Input
 Parallel Port multi-bit Output

9. For example
 IF we take pic microcontroller it have
five input output ports which are:
1.Port A
2.Port B
3.Port C
4.Port D
5.Port E

10. Pic18f458 (as example)
 PIC18F458 has totally 40 Pins, A total of
33 pins are set aside for the five
ports PORTA , PORTB, PORTC,
PORTD and PORTE .
 We can use these ports as
a INPUT OrOUTPUT ports. The rest of
the pins are designated for Vdd (Vcc) , Vss
(GND),OSC1,OSC2,MCLR(reset) and
another set of Vdd and Vss

11. Pins of ports
 PORTA 7 pins
 PORTB 8 pins
 PORTC 8pins
 PORTD 8 pins
 PORTE 3 pins

12. Block Diagram of I/O Interfacing
Access one port at a time
8-bit registers
I/O ports are associated with a SFR
Each port is associated with 3 registers:
PORT / LAT / TRIS
Buffer
Latch

13. PIC18F452/4520 I/O Ports (1 of 5)
 MCU includes five I/O ports
 PORTA, PORTB, PORTC, PORTD, and PORTE
 Ports are multiplexed meaning they can be
set up by writing instructions to perform
various functions

14. Interfacing Output Peripherals (1 of 2)
 Commonly used output peripherals in embedded systems are
 LEDs, seven-segment LEDs, and LCDs; the simplest is LED
 Two ways of connecting LEDs to I/O ports:
 LED cathodes are grounded and logic 1 from the I/O port turns on the
LEDs - The current is supplied by the I/O port called current sourcing.
 LED anodes are connected to the power supply and logic 0 from the
I/O port turns on the LEDs - The current is received by the chip called
current sinking.
Common Cathode Common Anode
Active high Active low

15. Interfacing Seven-Segment
LEDs as an Output (1 of 4)
 Seven-segment LEDs
 Often used to display BCD numbers (1 through
9) and a few alphabets
 A group of eight LEDs physically mounted in
the shape of the number eight plus a decimal
point as shown in Figure 9-5 (a)
 Each LED is called a segment and labeled as ‘a’
through ‘g’.

16. Interfacing Seven-Segment
LEDs as an Output (2 of 4)
 Two types of seven-segment
LEDs
 Common anode
 Common cathode
decimal point

17. Seven-Segment Chips
ALPHA/NUMERI
C C/A DISPLAY

18. Interfacing Input Peripherals
 Commonly used input peripherals in embedded
systems are:
1.Push button keys
2.Dip switches
3.Keyboard
4.Mouse
5.touchscreen

19. Output devices
1.LCD screen
2.Printer
3.PC’s
4.

20. Thank you !!!