embedded systems and its ports

EMBEDDED PRESENTATION

Prepared by :-Rahul sharma (11ece29)Nitin (11ece25)Piyush gupta (11ece27)Priya (11ece28)

Incharge:_Mr. Naresh TanwarECE department A.C.E.M

contents

1.Embedded system2.Port3.Port types4.Peripheral devices5.Interfacing6.Output devices

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.

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

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

I/O port types1.Serial input output ports2.Parallel input output ports

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.

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

For example IF we take pic microcontroller it have five input output ports which are: 1.Port A2.Port B3.Port C4.Port D5.Port E

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

Pins of ports

PORTA                    7 pins PORTB                     8 pins PORTC                     8pins PORTD                    8 pins PORTE                     3 pins

Block Diagram of I/O Interfacing

Access one port at a time8-bit registers I/O ports are associated with a SFREach port is associated with 3 registers: 

PORT / LAT / TRIS

Buffer

Latch

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

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

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’.

Interfacing Seven-Segment LEDs as an Output (2 of 4)

Two types of seven-segment LEDs Common anode Common cathode

decimal point

Seven-Segment Chips

ALPHA/NUMERIC C/A DISPLAY

Interfacing Input Peripherals

Commonly used input peripherals in embedded systems are:

1.Push button keys2.Dip switches3.Keyboard4.Mouse5.touchscreen

Output devices1.LCD screen2.Printer3.PC’s4.

Thank you !!!