introduction to pic16 microcontroller programming ... 1 am introductio… · 1 introduction to...

1

Introduction to PIC16Microcontroller Programming &

Interfacing

November 25-27, 2011Engr. Franz Duran, MEP-ECE

25-Nov-2011 Franz Duran 2

OVERVIEW

DAY 1 (Morning)

Introduction to PIC Microcontroller

PICTrainer3™ microcontroller laboratory/training module

MPLAB IDE

Basic C Programming


OVERVIEW

DAY 1 (Afternoon)

Basic C Programming… (cont.)

Intermediate C Programming

C Functions & Structured Programming

Modular Programming

Interfacing with 2x16 character LCD

Interfacing with 4x3 keypad

2


OVERVIEW

DAY 2 (Morning)

Basic of Interrupts

Interrupt sources

Interrupt service routine

RB0/INT interrupt

PORTB Interrupt on Change


OVERVIEW

DAY 2 (Afternoon)

PIC16 Timer module

TMR0 architecture

TMR0 as an interrupt source

Interfacing with 7-segment displays


OVERVIEW

DAY 3 (Morning)

Basic of Analog-to-Digital Conversion

Using the PIC16 A/D module

Interfacing LM35 temperature sensor

3


OVERVIEW

DAY 3 (Afternoon)

Basics of Serial Communication

PIC16 UART module

Basic string processing


MICROCONTROLLER

MCU, µC

A single-chip computer

Invented in the 1970’s

Used as “embedded” controller


MICROCONTROLLER

used as dedicated controllersdomestic appliances

consumer electronics

industrial equipments

automotive electronics

Naval/avionics/aerospace

4


MICROCONTROLLER

Why use?Cheap

Flexible

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 – 8th

1996 - 5th

1997-2001 – 2nd

2002 – Present – 1st

5


PIC MICROCONTROLLER

FamilyPIC10, PIC12

PIC16

PIC17 / PIC18

PIC24 / DSPICs (16-bit)

PIC32(32-bit)

Popular among students and hobbyists


PIC16 ARCHITECTURE

Program

Memory

Power

Reset, WatchdogTimer, etc

Oscillator

Internal Peripherals

General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU


PIC16 ARCHITECTURE

Program

Memory

Power


Oscillator


General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU

6


PIC16 ARCHITECTURE

CPUReduced Instruction Set Computer (RISC)

FOSC = 20MHz max. speed

FOSC/4 instruction clock


PIC16 ARCHITECTURE

Power


Oscillator


General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU

ProgramMemory


PIC16 ARCHITECTURE

Program Memory“hard drive” where fixed program is stored

flash-based memory

reprogrammable at least 10,000x

7


PIC16 ARCHITECTURE

Power


Oscillator


Input/Output

PortsCPU

Program

Memory

General Purpose

Registers

“Data RAM”

Special Function

Registers


PIC16 ARCHITECTURE

File RegistersGeneral Purpose Registers (GPRs)

Data RAM

Special Function Registers (SFRs)

control device operation


PIC16 ARCHITECTURE

Power


Oscillator


Input/Output

PortsCPU

Program

Memory

Special Function

Registers

General PurposeRegisters

“Data RAM”

8


PIC16 ARCHITECTURE

Power


Oscillator


Input/Output

PortsCPU

Program

Memory

General Purpose

Registers

“Data RAM”

Special FunctionRegisters


PIC16 ARCHITECTURE

Program

Memory

Power


Oscillator


General Purpose

Registers

“Data RAM”

Special Function

Registers

CPUInput/Output

Ports


PIC16 ARCHITECTURE

Program

Memory

Power


Oscillator

General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU


9


PIC16 ARCHITECTURE

Program

Memory


Oscillator


General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU

Power


PIC16 ARCHITECTURE

Program

Memory

Power



General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU

Oscillator


PIC16 ARCHITECTURE

Program

Memory

Power

Oscillator


General Purpose

Registers

“Data RAM”

Special Function

Registers

Input/Output

PortsCPU

Reset, Watchdog

Timer, etc

10


PIC16 ARCHITECTURE

Input/Output pins

Internal Peripherals/ModulesTimers

A/D converter module

UART

SPI / I2C

Comparator


PIC16 ARCHITECTURE

Features:Watchdog Timer

SLEEPmode

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)

11


PIC16F84A

8-bit microcontrolller“PIC16” – family

“F” – flash memory, i.e. reprogrammable

“84” – variant/model

“A” - revision

4Mhz (≈1MIPS), DIP18, +5V


PIC16F84A

Program Memory1024 instruction words

1 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 pin MCLR

12


PIC16F877A

20Mhz (≈5MIPS), DIP40, +5V

8192 instruction word

368 bytes Data RAM / GPRs

56 SFRs

256 bytes Data EEPROM


PIC16F877A

33 I/O pinsPORTA – 6 pins

PORTB – 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

13


PIC16F877A TRAINER BOARD10 LEDs

4 pushbuttons

3 potentiometers

serial comm. ckt.

character LCD

7-seg. display

keypad

4x3 or 4x4

DS1307

real-time IC

serial EEPROM IC

LM35 temp. sensor


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-TECH® C Compiler

45-day full version (full optimization)

Lite mode (no optimization)

direct support for ICD2/PICKIT2 programmer/debugger

eICD2, ePICKIT2

14


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)


MPLAB IDE 8.53

Open MPLAB – an example application


MPLAB IDE 8.53

To create new project: Project > Project Wizard

15


MPLAB IDE 8.53

Step 1: Select Device


MPLAB IDE 8.53

Step 2: Select Language


MPLAB IDE 8.53

Step 3: Select Project Name & Directory

16


MPLAB IDE 8.53

Step 4: Add files


MPLAB IDE 8.53

Project Summary


MPLAB IDE 8.53

Empty ProjectProject Window

Output Window

17


MPLAB IDE 8.53

Create source codeEditor Window


MPLAB IDE 8.53

#include <pic.h>

void main()

TRISB0 = 0;

RB0 = 1;

while(1)


MPLAB IDE 8.53

save as “main.c” in project directory

18


MPLAB IDE 8.53

main.c


MPLAB IDE 8.53

Add main.c Build project

(F10)


MPLAB IDE 8.53

19


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


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..

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BASIC PIC16F84A CKT.

PIC16F84A CIRCUIT1. PIC16F84A

2. +5v supply

3. Oscillator circuit

4. Reset circuit

5. External peripherals

6. In-circuit serial

programming

connector



PIC16F84A w/ +5V supply circuit



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

21



oscillator circuitgenerate a pulse train signal; used to

synchronize MCU internal operations



Reset circuit



Interfacing external peripherals

22




PIC16F877A Trainer Board


IO INTERFACING: LED

LED at RB0RB0 is output

23


LED

5mm LEDIF = 5 – 35 mA

VF = 2V

3mm LEDIF = 1 – 30 mA

VF = 2V


LED

IF

+

-

VF =

2v

+ -VR=3V

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

R = 300 Ω


LED

R should not be too largeLED will not turn on

R should not be too smallIF < 30mA

PIC Output pin source

current < 25mA

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BASIC I/O PROGRAM

Example I/O Program

#include <pic.h>

void main()

TRISB0 = 0;

RB0 = 1;

while(1)

preprocessor directive

main() function

initialization

program loop- infinite loop- super loop


IO PROGRAMMING

Input/Output port - group of 8 pins typical

PORTA – 6 I/O pins

RA5, RA4, RA3, RA2, RA1, RA0

PORTA<5:0>

PORTB – 8 I/O pins

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

PORTB<7:0>


IO PROGRAMMING

PORTC – 8 I/O pins

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

PORTC<7:0>

PORTD – 8 I/O pins

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

PORTD<7:0>

PORTE – 3 I/O pins

RE2, RE1, RE0

PORTE<2:0>

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IO PROGRAMMING

Special Function Registers for I/OTRISA, PORTA

TRISB, PORTB

TRISC, PORTC

TRISD, PORTD

TRISE, PORTE


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

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TRISB

TRISB0

TRISB1

TRISB7

. . . . . . . . .

.

.

.

0 – output1 – input

= XXXXXXXX



TRISB0

X X X X X X X X0

TRISB0 = 0; //RB0 is output

TRISB

RB0 pin is an output pin



PORTB

RB0

RB1

RB7

. . . . . . . . .

.

.

.

0 – Logic 01 – Logic 1

= XXXXXXXX

27



RB0

X X X X X X X X1

RB0 = 1; //LED on

PORTB

RB0 outputs a Logic 1 signal;

~5V



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

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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


IO PROGRAMMING

EXERCISE:Turn on all 8 LEDs connected to PORTD


IO PROGRAMMING

SOLUTION:TRISD = 0b00000000; //binary notation

PORTD = 0b11111111;

or

TRISD = 0x00; //hexadecimal notation

PORTD = 0xFF;

or

TRISD = 0; //decimal notation

PORTD = 255;

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IO INTERFACING: Button

pushbuttoninput device

Tack Switch



If button is not pressed

RIN

10k

+5v

+

-

≈1MΩV = 5v x 1MΩ / (R+1MΩ)

R

V ≈ 5v

RB2

(Logic 1)



If button is pressed

RIN+

-

~1MΩ V = 0v

RB2

(Logic 0)

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void 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.



R should be large enough to limit the

currentwhen button is

pressedI



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

configured as

output and at

Logic 0 (I/O pin

is internally

connected

to ground)

I < 25mA

31


BASICS OF C: #defines#include <pic.h>

__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;


BASICS OF C: Conditional

Statements

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

If()-else-if()

2. switch()


BASICS OF C: IF Conditional

Statement

If() Simplest conditional statement

if (condition)

statement1;

Ex.if(var>99)

var=0;

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Statement

If() use else clause (optional)

if (condition)

statement1;

else

statement2;

Ex.if(BUTTON==PRESSED)

LED=1;

else

LED=0;



Statement

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 is executed

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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


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 Loop

void 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<50000;i++) //delay

//empty body

RB0 = 0; //LED is OFF

for(i=0;i<50000;i++) //delay

//empty body

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for(i=0;i<50000;i++)

...//code goes here

i<50000?

i=0

TRUE

FALSE

//codes

exit

start

i++



i=0;

for( ;i<50000; )

//codes here

i++;

OR

for(i=50000;i>0;i--)

//codes here


BASICS OF C: WHILE Loop

while(condition)

...//code goes here

condition?

TRUE

FALSE

//codes

exit

start

35


BASICS OF C: WHILE Loop

EXERCISE:Modify previous example to used while()

loop


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, use while() loop

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

36


BASICS OF C: Variables

Variables

program data that varies during run-time

temporary data

placed in volatile memory

General Purpose Registers (GPR)

PIC16F877A

– 368 Bytes GPR


BASICS OF C: Variables

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

var1 = 100; //OK

var1 = 500; //not OK!

var1 = -10; //not OK!

signed 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-bit) (1.17549435e-38 - 3.40277e+38) double (24-bit) (1.17549435e-38 - 3.40277e+38 ) double (32-bit) (1.17549435e-38 - 3.40282347e+38 )

37


BASICS OF C: Operators

1.= (Assignment operator)

2. Mathematical operators

3. Relational operators

4. Logical operators

5. Bitwise operators



= (Assignment operator) x = y; //assign the value of y

//to the variable x

Variable name = expression

Expression - anything that evaluates to a number i.e.

int sum;

sum = a + b; //a + b is an expression



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

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Relational Operators

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

2.> (greater than) ex. x>y

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

4.< (lesser than) ex. x<y

5.<= (lesser than or equal to) ex. x<=y

6.!= (not equal to) ex. x!=y



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

39



Bitwise Operators1. & (Bitwise AND)

2. | (Bitwise OR)

3. ~ (Bitwise Complement)

4. ^ (Bitwise Exclusive-OR)

5. << (Leftshift)

6. >> (Rightshift)


BASICS OF C: & Operator

A B A & B

0 0 0

0 1 0

1 0 0

1 1 1

AND (&) operator truth table:



Bitwise-AND operator

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

Equivalent to: RB0 = 0; //clear RB0

40



Example:Clear PORTB<3:0> and RB6

Initial solution

RB0 = 0;

RB1 = 0;

RB2 = 0;

RB3 = 0;

RB6 = 0;

Alternative (better solution):PORTB = PORTB & 0b10110000;

PORTB &= 0b10110000;

PORTB &= ~0x4F;


BASICS OF C: | Operator

A B A | B

0 0 0

0 1 1

1 0 1

1 1 1

OR (|) operator truth table:


BASICS OF C: | Operator

Bitwise-OR operator

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

Equivalent to: RB0 = 1; //set RB0

41



Example:Configure PORTD<6:5> and PORTD<2:1> as

input: Initial solution

TRISD6=1;

TRISD5=1;

TRISD2=1;

TRISD1=1;

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

TRISD |= 0x66;



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

A B A | B

0 0 0

0 1 1

1 0 1

1 1 0

XOR (^) operator truth table:

42



Bitwise-XOR operatorToggle operator

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

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

PORTB ^= 0b00000011;



EXERCISE:Create a LED blinker application using ^

operator

Toggle two LEDs alternately


BASICS OF C: << and >> Operators

<< (shift left)

>> (shift right)

Ex:unsigned char var1 = 0b00000001;

PORTB = var1 << 2; //PORTB = 0b00000100

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END

introduction to pic16 microcontroller programming ... 1 am introductio… · 1 introduction to...

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