Day 1 AM Introduction

7/30/2019 Day 1 AM Introduction

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19-Aug-2010 Paranz 1

Introduction to PICMicrocontroller Programming &

Interfacing

August 19-21, 2010Franz Duran


OVERVIEW

DAY 1 (Morning)Introduction to PIC Microcontroller

PIC16F877A trainer board andeICD2/ePickit2 programmer/debugger

MPLAB IDE

Basic C Programming


OVERVIEW

DAY 1 (Afternoon)Basic C Programming (cont.)

C Functions

Modular Programming

Interfacing with 2x16 character LCD

Interfacing with 4x3 keypad


2/38


OVERVIEW

DAY 2 (Morning)Basic of Interrupts

Interrupt sources

Interrupt service routine

RB0 interrupt

PORTB Interrupt on Change


OVERVIEW

DAY 2 (Afternoon)Timer module

TMR0 architecture

TMR0 as an interrupt source

Interfacing with 7-segment displays

TMR1

TMR2


OVERVIEW

DAY 3 (Morning)Basic of Analog-to-Digital Conversion

Using the A/D module

Interfacing LM35 temp. sensor


3/38


OVERVIEW

DAY 3 (Afternoon)Basics of Serial Communication

UART module

Basic string processing

Interfacing with Bluetooth module

Interfacing with GSM module


MICROCONTROLLER

MCU, C

A single-chip computer

Invented in the 1970s

Used as embedded controller


MICROCONTROLLER

used as dedicated controllers

domestic appliances

consumer electronicsindustrial equipments

automotive electronics


4/38


MICROCONTROLLER

Why use?cheap

flexible

easy to develop applications

easy to maintain applications

small outline high integration

low-power


PIC MICROCONTROLLER

PIC, PICMICRO

by MICROCHIP

Arizona, U.S.A.

1989 (offshoot of General Instrument)

http://www.microchip.com


PIC MICROCONTROLLER

Rank (8-bit microcontroller)1990 20th

1993 8

th

1996 - 5th

1997-2001 2nd

2002 Present 1st


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PIC MICROCONTROLLER

FamilyPIC10, PIC12

PIC16

PIC17/PIC18

PIC24/DSPICs (16-bit)

PIC32(32-bit)

Popular amongstudents and hobbyists


PIC16 ARCHITECTURE

Program Memory hard drive where fixed program is stored

File RegistersGeneral Purpose Registers (GPRs)

Data RAM

Special Function Registers (SFRs)

control device operation

DATA EEPROMnon-volatile storage


PIC16 ARCHITECTURE

Input/Output pins

Internal Peripherals/Modules

TimersA/D converter module

UART

SPI / I2C

Comparator


6/38


PIC16 ARCHITECTURE

Features:Watchdog Timer

SLEEP mode

Power On Reset, Brown-out Reset

CPU

RISC (reduced instruction set computer)

FOSC = 20Mhz typical


PIC16 ARCHITECTURE

Instruction set35 instructions (PIC16)

Easy to memorize all instructions

75 instruction (PIC18)


PIC16F84A

8-bit microcontrolllerPIC16 family

F flash memory, i.e. reprogrammable

84 variant/model

A - revision

4Mhz (1MIPS), DIP18, +5V


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PIC16F84A

Program Memory

1024 instruction words1 word = 14 bit

File Registers (2 banks)GPRs - 68 bytes RAM

SFRs 16 registers

Data EEPROM64 bytes


PIC16F84A

13 I/O pinsPORTB 8 pins

PORTA 5 pins

2 power pinsVDD, VSS

2 oscillator pinsOSC1, OSC2

1 RESET pinMCLR


PIC16F877A

20Mhz (5MIPS), DIP40, +5V

8192 instruction word

368 bytes Data RAM / GPRs56 SFRs

256 bytes Data EEPROM


8/38


PIC16F877A

33 I/O pins

PORTA 6 pinsPORTB 8 pins

PORTC 8 pins

PORTD 8 pins

PORTE 3 pins

4 power pins

1 Reset, 2 Clock pins


PIC16F877A TRAINER BOARD

PIC16F877A

Reset Button

20Mhz Oscillator

+5V supply

ICSP connector

SIL connectors


PIC16F877A TRAINER BOARD10 LEDs

4 pushbuttons

3 potentiometers

serial comm. ckt.

character LCD

7-seg. display

keypad

4x3 or 4x4

DS1307real-time IC

serial EEPROM IC

LM35 temp. sensor


9/38


PIC16F877A & eICD2

Connect wires to build application circuit

eICD2

ICSP connector


MPLAB IDE 8.xx

integrated development environment

(IDE) for PIC freely downloadable (~90MB)

assembler (MPASM)

HI-TECHC Compiler 45-day full version (full optimization)

Lite mode (no optimization)

direct support for ICD2/PICKIT2programmer/debugger eICD2, ePICKIT2


MPLAB IDE 8.xx

Download and Install MPLABhttp://www.microchip.com

Install HI-TECH

Compilerincluded in the MPLAB installer

or download separately from:

http://www.htsoft.com

HI-TECH Sofware

Brisbane, Australia

bought by Microchip (March 2009)


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MPLAB IDE 8.53

Open MPLAB an example application


MPLAB IDE 8.53

To create new project:Project > Project Wizard


MPLAB IDE 8.53

Step 1: Select Device


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MPLAB IDE 8.53

Step 2: Select Language


MPLAB IDE 8.53

Step 3: Select Project Name &Directory


MPLAB IDE 8.53

Step 4: Add files


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MPLAB IDE 8.53

Project Summary


MPLAB IDE 8.53

Empty ProjectProject Window

Output Window


MPLAB IDE 8.53

Create source codeEditor Window


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MPLAB IDE 8.53#include

void main()

{

TRISB0 = 0;

RB0 = 1;

while(1)

{

}

}


MPLAB IDE 8.53

save as main.c in project directory


MPLAB IDE 8.53

main.c


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MPLAB IDE 8.53

Addmain.c Build project

(F10)


MPLAB IDE 8.53


WHY C? (& not ASM?)

1. Easy to Use Easy to read

C uses human readable syntax

Assembly uses mnemonics (cryptic!) Shorter code

saves time & effort

easy math statements

2. Portable code can run in other target device

no or few modifications, saves time and effort


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WHY C? (& not ASM?)

3. Easy to manage large, complex

programs code reuse of C modules (.h & .c)

Easy to implement state machines

Can use RTOS, not possible in ASM

4. Better performance C can be as fast as ASM

well structured program

C codes can include ASM codes


WHY C? (& not ASM?)

5. C is a universal language(almost!) Learning C will benefit the user down the

road

Can be used in other 8-bit/16-bit/32-bit MCU

implement USB, Ethernet & TCP-IP applications

DSP

Learn desktop programming

foundation for C++, Java, C#, etc..


BASIC PIC16F84A CKT.

PIC16F84A CIRCUIT1. PIC16F84A

2. +5v supply

3. Oscillator circuit

4. Reset circuit

5. External peripherals

6. In-circuit serial

programming

connector


16/38



PIC16F84A w/ +5V supply circuit



PIC16F84A w/ +5V supply circuit & crystaloscillator and loading capacitors



oscillator circuitgenerate a pulse train signal; used to

synchronize MCU internal operations


17/38



Reset circuit



Interfacing external peripherals




18/38


PIC16F877A Trainer Board


IO INTERFACING: LED

LED at RB0RB0 is output


LED

5mm LEDIF = 5 35 mA

VF = 2V

3mm LEDIF = 1 30 mA

VF = 2V


19/38


LED

IF

+

-

VF =

2v

+ -VR=3V

If IF = 10mA,R = 3V/10mA

R = 300


LED

R should not be too largeLED will not turn on

R should not be too smallIF < 30mA

PIC Output pin source

current < 25mA


BASIC I/O PROGRAM Example I/O Program

#include

void main()

{

TRISB0 = 0;

RB0 = 1;

while(1)

{

}

}

preprocessor directive

main() functioninitialization

program loop- infinite loop- super loop

Example#1


20/382


IO PROGRAMMING

Input/Output port - group of 8 pinstypicalPORTA 6 I/O pins

RA5, RA4, RA3, RA2, RA1, RA0

PORTA

PORTB 8 I/O pins

RB7, RB6, RB5, RB4, RB3, RB2, RB1, RB0

PORTB


IO PROGRAMMING

PORTC 8 I/O pins

RC7, RC6, RC5, RC4, RC3, RC2, RC1, RC0

PORTC

PORTD 8 I/O pins

RD7, RD6, RD5, RD4, RD3, RD2, RD1, RD0

PORTD

PORTE 3 I/O pins

RE2, RE1, RE0

PORTE


IO PROGRAMMING

Special Function Registers for I/OTRISA, PORTA

TRISB, PORTB

TRISC, PORTC

TRISD, PORTD

TRISE, PORTE


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IO PROGRAMMING

Consider PORTB..


IO PROGRAMMING: SFRs

PORTB port controlled by 2 special function registers

1. TRISB register PORTB Data Direction Register

8-bit

2. PORTB register PORTB Data Latch Register

8-bit



TRISB

TRISB0

TRISB1

TRISB7

. . . . . . . . .

.

.

.

0 output1 input

= XXXXXXXX


22/382



TRISB0

X X X X X X X X0

TRISB0 = 0; //RB0 is output

TRISB

RB0 pin isan output pin



PORTB

RB0

RB1

RB7

. . . . . . . . .

.

.

.

0 Logic 01 Logic 1

= XXXXXXXX



RB0

X X X X X X X X1

RB0 = 1; //LED on

PORTB

RB0 outputs aLogic 1 signal;

~5V


23/382



TRISB0 = 0; //RB0 is output

RB0 = 1; //LED is on

X X X X X X X

X X X X X X X

0

1

TRISB

PORTB


IO PROGRAMMING

EXERCISE:Create new project

Led_demo_2

Turn on LEDs connected to the ff. I/O pins: RB0, RA1, RC3, RD7, RE2

Example#2


IO PROGRAMMING

EXERCISE: (Solution)TRISB0 = 0;

RB0 = 1; //LED1 on

TRISC3 = 0;

RC3 = 0; //LED2 on

TRISD7 = 0;

RD7 = 1; //LED3 on

ADCON1 = 0x06; //All PORTA & PORTE pins are digital I/O

TRISA1 = 0;

RA1 = 1; //LED4 on

TRISE2 = 0;

RE2 = 0; //LED5 on

Example#2


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IO PROGRAMMING

EXERCISE:Turn on all 8 LEDs connected to PORTD

Example#3


IO PROGRAMMING

SOLUTION:TRISD = 0b00000000; //binary notation

PORTD = 0b11111111;

or

TRISD = 0x00; //hexadecimal notation

PORTD = 0xFF;

or

TRISD = 0; //decimal notation

PORTD = 255;

Example#3


IO INTERFACING: Button

pushbuttoninput device

Tack Switch


25/382



If button is not pressed

RIN

10k

+5v

+

-

1MV = 5v x 1M / (R+1M)

R

V 5v

RB2

(Logic 1)



If button is pressed

RIN +

-

~1M V = 0v

RB2

(Logic 0)


IO INTERFACING: Buttonvoid main()

{

TRISB0 = 0; //RB0 is an output pin

RB0 = 0; //LED is off

TRISB2 = 1; //RB2 is an input pin

while(1)

{

if(RB2==0) //If button is pressed,

RB0 = 1; // LED is on,

else //else,

RB0 = 0; // LED is OFF.

}

}

Example#4


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R should be large enough to limitthe currentwhen button is

pressed I



R should be large enough to limitthe currentwhen I/O pin is

configured as

output and at

Logic 0 (I/O pinis internally

connected

to ground)

I < 25mA


BASICS OF C: #defines#include

__CONFIG(HS & WDTDIS & PWRTDIS & UNPROTECT & LVPDIS);

#define LED RB0

#define BUTTON RB2

#define ON 1

#define OFF 0

#define PRESSED 0

void main()

{

TRISB0 = 0; //RB0 is an output pin

LED = OFF; //LED is initially off

TRISB2 = 1; //RB2 is an input pin

while(1)

{

if(BUTTON==PRESSED) //If pushbutton is pressed,

LED = ON; // turn on LED.

else //Else, LED is OFF.

LED = OFF;

}

}

Example#5


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BASICS OF C: ConditionalStatements

1. If() If()-else()

If()-else-if()

2. switch()


BASICS OF C: IF ConditionalStatement

If() Simplest conditional statement

if (condition)

statement1;

Ex.if(var>99)

var=0;


BASICS OF C: IF ConditionalStatement If()

use elseclause (optional)

if (condition)

statement1;

else

statement2;

Ex.if(BUTTON==PRESSED)

LED=1;

else

LED=0;


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BASICS OF C: IF ConditionalStatement

If()-else-if() if (condition1)

statement1;

else if (condition2)

statement2;

else if (condition3)

statement3;

else

statement4;


BASICS OF C: Switch()

switch()Allow comparison of a single variable (or

expression) to multiple values

Code associate with the matching value isexecuted


BASICS OF C: Switch()var1 = get_input_from_user()

switch(var1)

{

case 0x00:

statement1;

break;case 0x01:

statement2;

break;

case 0x02:

statement3;

break;

case 0x03:

statement4;

break;

default:

statement5;

break

}


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BASICS OF C: Loops

Loops used to repeatedly execute specific

statements

3 loop statements in C1. for() loop

2. while() loop

3. do-while() loop


BASICS OF C: FOR Loopvoid main()

{

unsigned int i; //a variable.

TRISB0 = 0; //RB0 pin is configured as an output

RB0 = 0; //LED is initially off

while(1)

{

RB0 = 1; //LED is ON

for(i=0;i


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BASICS OF C: FOR Loop

i=0;

for( ;i0;i--)

{

//codes here

}


BASICS OF C: WHILE Loop

while(condition)

{

...//code goes here

}

condition?

TRUE

FALSE

//codes

exit

start


BASICS OF C: WHILE Loop

EXERCISE:Modify previous example to used while()

loop

Example#7


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BASICS OF C: DO-WHILE Loop

do

{

...//code goes here

}

while(condition);

condition?

TRUE

FALSE

//codes

exit

start


BASICS OF C: Loops

Which loop statements to use?If number of iteration is controlled, use for()

loop

If a simple test of condition is used, usewhile() loop

If a simple test of condition is used ANDthecode block should be executed at least once,use do-while() loop


BASICS OF C: Variables

Variables

program data that variesduring run-time

temporary dataplaced in volatile memory

General Purpose Registers (GPR)

PIC16F877A

368 Bytes GPR


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BASICS OF C: Variables

unsigned char var1; //range of values: 0-255

var1 = 100; //OK

var1 = 500; //not OK!

Var1 = -10; //not OK!

char var2; //range of values: -128 to 127

var2 = 100; //OK

var2 = -1000; //not OK!

var2 = 150; //not OK!

unsigned int temp = 100; // range of values: 0-65535

temp = 50000; //OK

temp = 100000; //not OK!


BASICS OF C: Variables bit (1-bit) (0 1) char (8-bit) (-128 127) unsigned char (8-bit) (0 255) short (16-bit) (-32768 32767) unsigned short (16-bit) (0 65535) int (16-bit) (-32768 32767) unsigned int (16-bit) (0 65535) short long (24-bit) ( -8388608 8388607) unsigned short long (24-bit) (0 16777215) long (32-bit) (21474833648 2147483647) unsigned long (32-bit) (0 4294967295) float (24-bi t) (1.17549435e-38 - 3.40277e+38) double (24-bi t) (1.17549435e-38 - 3.40277e+38 ) double (32-bit) (1.17549435e-38 - 3.40282347e+38 )


BASICS OF C: Operators

1.= (Assignment operator)

2. Mathematical operators

3. Relational operators

4. Logical operators

5. Bitwise operators


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= (Assignment operator)

x = y; //assign the value of y to//the variable x

Variable name = expression

Expression - anything that evaluates to anumber i.e.

int sum;

sum = a + b; //a + b is anexpression



Mathematical operators1. + (addition) ex. x + y

2. - (subtraction) ex. x - y

3. * (multiplication) ex. x * y

4. / (division) ex. x / y

5. % (modulus) ex. x % y

6. ++ (increment) ex. x++, ++x

7. -- (decrement) ex. x--, --x



Relational Operators

1.== (equal to) ex. x==y

2.> (greater than) ex. x>y3.>= (greater than or equal to) ex. x>=y

4.< (lesser than) ex. x


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Logical Operators1. && (Logical AND)

2. || (Logical OR)

3. ! (Logical NOT)



EXERCISE:Turn on LED1 if BUTTON1 or BUTTON2

is pressed

Modify: Turn on LED1 if BUTTON1 and BUTTON2

are pressed



Bitwise Operators1. & (Bitwise AND)

2. | (Bitwise OR)3. ! (Bitwise Complement)

4. ^ (Bitwise Exclusive-OR)

5. > (Rightshift)


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BASICS OF C: & Operator

111

001

010

000

A & BBA

AND (&) operator truth table:



Bitwise-AND operator

Example: RB0 = RB0 & 0; //clear RB0

Equivalent to: RB0 = 0; //clear RB0



Example:Clear PORTD and RB6

Initial solution

RB0 = 0;RB1 = 0;

RB2 = 0;

RB3 = 0;

RB6 = 0;

Alternative (better solution):

PORTB = PORTB & 0b10110000;

PORTB &= 0b10110000;

PORTB &= ~0x4F;


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BASICS OF C: | Operator

111

101

110

000

A | BBA

OR (|) operator truth table:


BASICS OF C: | Operator

Bitwise-OR operator

Example: RB0 = RB0 | 1; //set RB0

Equivalent to: RB0 = 1; //set RB0



Example:Configure PORTD and PORTD as

input:

Initial solutionTRISD6=1;

TRISD5=1;

TRISD2=1;

TRISD1=1;

Alternative (better solution):TRISD = TRISD | 0b01100110;

TRISD |= 0x66;


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Masking techniqueTo clear a bit (or bits), AND this bit with 0

To set a bit (or bits), OR this bit with 1

Ex: PORTB &= 0b10110000;

TRISD |= 0x66;

Mask values


BASICS OF C: ^ Operator

011

101

110

000

A | BBA

XOR (^) operator truth table:



Bitwise-XOR operatorToggle operator

Example: RB0 = RB0 ^ 1; //toggle RB0

Equivalent to: RB0 = !RB0; //toggle RB0


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EXERCISE:Create a LED blinker application using ^

operator

Toggle two LEDs alternately every 500ms


BASICS OF C: >

Operators

> (shift right)

Ex:unsigned char var1 = 0b00000001;

PORTB = var1

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