Lecture 5-Embedde.pdf

Lecture 5
INTRODUCTION TO
MICROCONTROLLER
Microprocessor & Microcontroller System

Intended Learning outcomes
 At the end of this topic, students should be
able to:
 eplain briefly the microcontroller-based system
using block diagram.
 list the types of microcontroller and examples of
embedded microcontroller/ embedded system
 describe the features and internal structure of a
microcontroller (PIC16F877A).
 describe how an instruction is executed.
1

Introduction
What is a microcontroller?
 A microcontroller (sometimes abbreviated µC, uC
or MCU) is a small computer on a single integrated
circuit containing a processor core, memory, and
programmable input/output peripherals. It can only
perform simple task. A microcontroller is often
described as a ‘computer-on-a-chip’.
2

 Microcontrollers are purchased ‘blank’ and then
programmed with a specific control program.
 Once programmed the microcontroller is build into a
product to make the product more intelligent and
easier to use.
 A designer will use a Microcontroller to:
- Gather input from various sensors
- Process this input into a set of actions
- Use the output
mechanisms on
the microcontroller
to do something
useful.
3

The Difference between microcomputer system
and microcontroller based system
4

 Microcontrollers are sometimes called embedded
microcontrollers, which just means that they are
part of an embedded system -- that is, one part
of a larger device or system.
 The majority of microcontrollers in use today are
embedded in other machinery, such as
automobiles, telephones, appliances, and
peripherals for computer systems. These are
called embedded system.
Embedded System
6

…cont’d
 Typical input and output devices include
switches, relay, solenoids, LEDs, small or custom
LCD displays, radio frequency devices, and
sensors for data such as temperature, humidity,
light level etc.
 Embedded systems usually have no keyboard,
screen, disks, printers, or other recognizable I/O
devices of a personal computer, and may lack
human interaction devices of any kind.
7

9
Examples of Embedded System
 Consumer Electronic : DVD player, hi-fi, TV, air-conditioner, washing
machine etc.
 Medical Monitoring Devices : ECG (electrocardiogram), blood
pump, blood pressure meter, etc.
 Security System : Alarm, remote sueveilance, smart card + reader etc.
 Closed Loop Process Control : Motor speed control, robot, SCADA
(supervisory control & acquisition) etc.
 Personal Computing : Keyboard, printer, USB hub, SCSI HD, energy
management etc.
 Automotive : Ignition control, A/C, Automatic transmission, anti-lock
brake system (ABS), active suspension, etc
 Military : Missile, torpedo, ejection seat, etc
 Communications : Handphone, modem, radio, radar, satelite etc.
9
8

Types of Microcontroller
 Parallax Propeller
 Freescale 68HC11 (8-bit)
 Intel 8051
 Silicon Laboratories Pipelined 8051 Microcontrollers
 ARM processors (from many vendors) using ARM7 or Cortex-M3
cores are generally microcontrollers
 STMicroelectronics STM8 (8-bit), ST10 (16-bit) and STM32 (32-bit)
 Atmel AVR (8-bit), AVR32 (32-bit), and AT91SAM (32-bit)
 Freescale ColdFire (32-bit) and S08 (8-bit)
 Hitachi H8, Hitachi SuperH (32-bit)
 Hyperstone E1/E2 (32-bit, First full integration of RISC and DSP on
one processor core [1996])
 Infineon Microcontroller: 8, 16, 32 Bit microcontrollers for
automotive and industrial applications.
10
9

 MIPS (32-bit PIC32)
 NEC V850 (32-bit)
 Microchip PIC (8-bit PIC16, PIC18, 16-bit dsPIC33/PIC24)
 PowerPC ISE
 PSoC (Programmable System-on-Chip)
 Rabbit 2000 (8-bit)
 Texas Instruments Microcontroller MSP 430 (16-bit), C2000
(32-bit), and Stellaris (32-bit)
 Toshiba TLCS-870 (8-bit/16-bit)
 Zilog eZ8 (16-bit), eZ80 (8-bit)
 etc
…cont’d
10

 PIC is a family of Harvard architecture
microcontroller made by Microchip Technology. The
name PIC initially referred to "Peripheral Interface
Controller“ . PIC microcontrollers were the first RISC
microcontroller.
 PICs are popular with both industrial developers and
hobbyists alike due to their low cost, wide
availability, large user base, extensive collection of
application notes, availability of low cost or free
development tools, and serial programming (and re-
programming with flash memory) capability.
Microchip PIC
11

Two Different Architectures
12

PIC Microcontroller product family
 8-bit microcontrollers
 PIC10
 PIC12
 PIC14
 PIC16
 PIC17
 PIC18
 PIC24F
 PIC24H
 PIC32
 16-bit digital signal
controllers
 dsPIC30
 dsPIC33F
13

 The F in a name generally indicates the PICmicro uses flash
memory and can be erased electronically.
 The C generally means it can only be erased by exposing the
die to ultraviolet light (which is only possible if a windowed
package style is used). An exception to this rule is the PIC16C84
which uses EEPROM and is therefore electrically erasable.
1 :
14
PIC Microcontroller product family

Why use PIC16F877?
15
 Why PIC16F877A is very popular?
 This is because PIC16F877A is very cheap. Apart from that
it is also very easy to be assembled. Additional components
that you need to make this IC work is just a 5V power supply
adapter, a 20MHz crystal oscillator and 2 units of 22pF
capacitors.
 What is the advantages of PIC16F877A?
 This IC can be reprogrammed and erased up to 10,000
times. Therefore it is very good for new product
development phase.
 What is the disadvantages of PIC16F877A?
 This IC has no internal oscillator so you will need an external
crystal of other clock source.

Features of
PIC16F877
16
8
Key Features PIC16F877
MAX Operating Frequency 20MHz
FLASH Program Memory
(14-bit words)
8K
Data Memory (bytes) 368
EEPROM Data Memory (bytes) 256
I/O Ports
RA0-5 (6)
RB0-7 (8)
RC0-7 (8)
RD0-7 (8)
RE0-2 (3)
Timers 3
CCP 2
Serial Communications MSSP, USART
Parallel Communications PSP
10-bit Analog-to-Digital Module 8 Channels
Instruction Set 35 Instructions
Pins (DIP) 40 Pins

 As you can see the
PIC16F877A is rich
in peripherals so you
can use it for many
different projects.
Bubble diagram
of PIC16F877
17

 Quad Flat Package
(QFP)
 Plastic Leaded Chip Carrier Package
(PLCC)
Pin Diagram of PIC16F877
18

Pin Diagram
of PIC16F877
19
 Plastic dual in-line
package (DIP)

 The basic architecture of PIC16F877 consists of
Program memory, file registers and RAM, ALU and
CPU registers.
PIC16F877
Internal Block Diagram
PIC16F877 Internal Block Diagram
21

Memory of the PIC16F877
 divided into 3 types of memories:
1. Program Memory – A memory that contains the program (which we
had written), after we've burned it. As a reminder, Program Counter
executes commands stored in the program memory, one after the other.
2. Data Memory – This is RAM memory type, which contains a special
registers like SFR (Special Function Register) and GPR (General Purpose
Register). The variables that we store in the Data Memory during the
program are deleted after we turn of the micro. These two memories have
separated data buses, which makes the access to each one of them very
easy.
3. Data EEPROM (Electrically Erasable Programmable Read-Only
Memory) – A memory that allows storing the variables as a result of
burning the written program.
22

 Each one of them has a different role. Program
Memory and Data Memory two memories that are
needed to build a program, and Data EEPROM is
used to save data after the microcontroller is turn off.
…cont’d
23

 Is Flash Memory
 Used for storing compiled
code (user’s program)
 Program Memory capacity is
8K x 14 bit  Each location
is 14 bits long
 Every instruction is coded
as a 14 bit word
 PC can address up to 8K
addresses
 Addresses H’000’ and
H’004’ are treated in a
special way
PIC16F877A
Program Memory
24

PIC16F877A Data Memory (RAM)
25
 Memory storage for variables
 Data Memory is also known as Register File and consists of two
components.
 General purpose register file (same as RAM).
 Special purpose register file (similar to SFR in 8051).
 Addresses range from 0 to 511 and partitioned into 4 banks 
each bank extends up to 7Fh (128 bytes).
 The user can only access a RAM byte in a set of 4 banks and
only one bank at a time. The default bank is BANK0.
 To access a register that is located in another bank, one should
access it inside the program. There are special registers which
can be accessed from any bank, such as STATUS register.

PIC16F877A register file map
26

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