The document provides an overview of embedded systems and their components, particularly focusing on microcontrollers such as the PIC16F877A. It details the architecture, functionality, and programming of these systems, including examples of code to control outputs on various ports. Key features are highlighted, including microcontroller specifications, applications, and practical programming techniques for LED control.

1. Introduction To
Embedded System
AR LABS
(A TRAINING UNIT OF METACORTEX
TECHNOLOGIES)

2. EMBEDDED SYSTEMS ??

3. LITERAL MEANING
EMBEDDED SYSTEM

4. BASIC DEFINTION
EMBEDDED SYSTEM: Combination of computer hardware &
software, that is specifically designed for a particular kind of
application device.

5. APPLICATIONS ARE NUMEROUS

6. APPLICATIONS OF EMBEDDED SYSTEM
Automotive electronics
Aircraft
Telecommunication
Trains

8. Specialties Of Embedded Systems
Performance Power Cost Size Software Up
Consumption gradation
capability
HIGH LOW CHEAP SMALL HIGH

9. BLOCK DIAGRAM OF EMBEDDED SYSTEM

10. CONTROLLING UNIT/BRAIN
Brain is the main part of the EMBEDDED SYSTEM
or main centre of information processing.
For an embedded system designer knowledge of
controlling unit or processor is a must.
The brain is often a microprocessor or
microcontrollers.

11. BRAIN
BRAIN
Microprocessors Microcontrollers
32 bit 64 bit 8 bit 16 bit 32 bit
DSPs, PC CISC RISC

12. MICROPROCESSORS
CPU for Computers
No RAM, ROM, I/O on CPU chip itself
Data Bus Many chips on mother board
CPU
General-
Purpose Serial
Micro- RAM ROM I/O Timer COM
processor Port Port
Address Bus
General-Purpose Microprocessor System

13. Where to find microprocessors

14. What is a Microcontroller????????

15. Where To Find Microcontrollers?
• Microcontroller are found everywhere!
• uC’s are considered embedded systems

16. Microprocessor Microcontroller
CPU is stand- CPU, RAM, ROM, I/O
alone, RAM, ROM, I/O, timer and timer are all on a
are separate
single chip
designer can decide on the
amount of ROM, RAM and I/O
ports.
v/s fix amount of on-chip
ROM, RAM, I/O ports
for applications in
which cost, power
expensive and space are critical
single-purpose
general-purpose

17. COMMONLY USED CONTROLLERS..
<< ADVANCED
VIRTUAL RISC –AVR
8051 CONTROLLER BY PERIPHERAL
INTEL / AT89C51 INTERFACE
CONTROLLER (PIC)
ADVANCE RISC
MACHINE (ARM)

18. MICROCONTROLLER MANUFACTURERS
o ATMEL
o MICROCHIP
o TEXAS INSTRUMENTS
o INTEL
o FREESCALE

19. PIC 16F877A
Owned & Developed By
Microchip

21. Analog features
• 10 bit ADC
• Brownout reset
Memory
feature
Special UC • 368 bytes
• IN Circuit Pic16f877a of RAM
Serial • 256 bytes
Programmi 8 bit uc of EEPROM
ng • 8K FLASH
PROGRAM
MEMORY
Peripheral
• USART
• 8 & 16 bit Timer Counter

22. 40/44-pin
20 Mhz Clock
Input
8K x 14 words
256 x 8 bytes
EEPROM

23. SHOWING FIVE PORTS in uc
Vpp 1 40 RB7
RA0 2 39 RB6
RA1 3 38 RB5
PORT A RA2 4 37 RB4
PORT B
RA3 36 RB0 - RB7
RA0-RA5 RA4
5
35
RB3
6 RB2
RA5 7 34 RB1
RE0 8 33 RB0
PORT E RE1 9 32 Vdd
RE0 – RE1 RE2 10 PIC16F 31 Vss
PORT D
Vdd 11 30 RD7
Vss 12 877A 29 RD6
RD7 – RD4
Oscillator CLK1 13 28 RD5 Higher Nibble
CLK0 14 27 RD4
PORT C RC0 15 26 RC7 PORT C
RC0-RC4 RC1 16 25 RC6 RC4-RC7
Lower RC2 17 24 RC5 Higher Nibble
Nibble RC3 18 23 RC4
RD0 19 22 RD3
RD1 20 21 RD2
PORT D
RD0 - RD3
Lower Nibble

25. Steps to perform
Write the program in PIC C.
Now burn the hex file using pic downloader.
Give Connections of Led’s on one port.

26. Points To Remember
We have 5 bidirectional PORTS in our controller.
Any peripheral will be connected to these ports only.
The value on these ports decides the functionality of
peripheral

27. Points To Remember
There are some predefined functions under the header
file <pic16f877a.h> which we use
1.output_low(pin_x): Used to make particular pin low(0)
2.output_high(pin_x):Used to make particular pin
high(1)
3.Output_port(value): using this function ,value is
loaded on the port.

28. 1=ON
0=Off
For e.g. we want to send
a value like 15 on port B
In binary It means
00001111
We will write
Output_port(15)
Red = on =1
Blue =Off=0

29. another e.g.
we want to send value
now 116 on port D
In binary It means
01110100
We will write
Output_port(116)
Red = on =1
Blue =Off=0

30. # include Header files
#Use clock
Void main() {
WHILE(1)
{
Output_port(y)
} while loop
END
Main
loop end

31. Body of Program
1. Include Header FILE
2. Specify Clock
3. Void main() {
4. Infinite LOOP {
Output_port( x)
}}

32. To Blink a Single LED
#include<16f877a.h> //Header file to specify device
#use delay(clock=20000000) //Definition of frequency
void main()
{
int x = 0; // Variable initialization
while(1)
{
output_high(pin_a0); //sets the pin a0
delay_ms(400); // delay of 400ms
output_low(pin_a0); //clears the specified pin. a0 in this case
delay_ms(400);
}

33. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1) After coming
{ to while(1), it
output_high(pin_a0); stuck in
infinite loop
delay_ms(400);
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

34. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
output_high(pin_a0);
delay_ms(400);
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

35. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
Used to make pin a0
output_high(pin_a0);
high
delay_ms(400); i.e., to glow led
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

36. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
output_high(pin_a0); Used to generate
delay_ms(400); delay of 400ms.
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

37. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
output_high(pin_a0);
delay_ms(400);
output_low(pin_a0); Used to make pin a0
delay_ms(400); low
i.e., to off led
}
How Program Actually Works

38. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
output_high(pin_a0);
delay_ms(400);
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

39. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
output_high(pin_a0);
delay_ms(400);
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

40. #include<16f877a.h>
#use delay(clock=20000000)
void main()
{
int x = 0;
while(1)
{
output_high(pin_a0); & so on..
delay_ms(400);
output_low(pin_a0);
delay_ms(400);
}
How Program Actually Works

41. TO Blink ALL LED
#include<16f877a.h> // Header file to add the device
#use delay(clock=20000000) // defination of frequency
void main()
{
int x = 0; // port data variable initialization
while (1)
{
output_b(x); // data sent to port b
delay_ms(400); // delay of 400ms
x= x^255; // XOR with 225 to complement the
} // data
}