Simple Microcontroller
Programming with PIC16F88.
ECE 3102/ ECE 4102
International Islamic University Malaysia
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ABOUT MICROCONTROLLER
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Microcontroller in Common Modern Appliances
Microcontrollers typically have the same functions like
Computer yet it is much smaller and cheaper. It can be used
in everyday appliances such as washing machine, modern
car, mobile robot and home appliances.
Computer: big size
Microcontroller: mini size
4cm x 2 cm or smaller.
Microcontroller also consumes less energy.
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Some Appliances Using Microcontroller
AC
Rice Cooker
Washing machine
Electric chair
Auto gate
Modern car
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Introduction to Microcontroller
Microcontroller, also called as MCU or C, is an integrated electric circuit (IC)
having some properties to perform like computer i.e: CPU (Central Processing
Unit), code memory, data memory and I/O port.
Its small size allows to be embedded into various home and industrial appliances,
robotic applications and etc.
RAM
ROM
Digital
I/O
Serial
I/O
ADC
Timer/
Counter
function
Small
Layout
PWM
Cheap
High Speed
Low Power
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Microcontroller: Practical in Use
The command/
program is written
in BASIC or C and
transferred into the
memory of the
Microcontroller via
programmer or
writer device.
Computer
Blank
Microcontroller
Programmer/
writer
After the Microcontroller is
programmed, then it is
ready to use in the
application.
Application unit
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Preparation to Microcontroller Programming
Software:
Compiler MikroC can be downloaded freely from:
http://www.mikroe.com
Data transformer to Microcontroller: Winpic800.
Download free from: http://www.winpic800.com
Hardware:
Programmer
Application circuit)
Programmer
Example of application circuit
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Programmer Circuit
5volt power supply
Resistor:
100 W or 56W
This Programmer uses external 5V power supply.
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Simple Programmer
This Programmer does not
use external power supply
but sources the power
directly from serial port.
More convenient.
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Simple Application Circuit
The available ports can be directly
connected to LED, Transistor, Buzzer,
Sensor and Actuator.
Oscillator
(10k – 20MHz)
Minimal component to drive
Microcontroller:
•IC Microcontroller
•External Power supply, 5 V
The Oscillator seems to have same
function as heart in our body. It is to
trigger constant pulses to execute the
program in Microcontroller.
•Fixed Frequency Oscillator
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Important Notice in Microcontroller Operation
1. Microcontroller PIN location must be correct. Check properly the
Socket direction by looking at PIN mark or number.
2. Switch Off the power supply when assembling and dismantling the
Microcontroller to and from the Socket.
3. Don’t touch the Microcontroller on the PINs since our body include
static electricity. The IC may be sensitive. Use pincer or small
screwdriver to assist the IC removal from socket.
4. Check the voltage of the supply for safety. Input voltage can not be
more than the specified (e.g. 5volt, 9volt).
5. Work carefully during IC dismantling since the PINs of IC and socket
are fragile.
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Input – Output (I/O) Microcontroller
I/O configuration can be seen on the Datasheet of the Microcontroller.
Input of Microcontroller can be
digital or analog.
If digital, then 0V input for low (0)
and 5V for high (1).
If analog, then input range is from
0V to 5V.
Output of Microcontroller is only
digital; 0V for state 0 and 5V for
state 1.
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Port I/O Microcontroller
Example: From datasheet Microcontroller
PIC16F88:
Pin Input Analog (AN0-AN6):
17,18,1,2,3,12,13
Pin Input Digital:
PORT A (RA0-RA4): 17,18,1,2,3
PORT B (RB0-RB7): 6,7,8,9,10,11,12,13
Pin Output only digital:
PORT A (RA0-RA4): 17,18,1,2,3
PORT B (RB0-RB7): 6,7,8,9,10,11,12,13
PIN can be assigned as input or output depending on the programming
setting.
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Digital Value of Port I/O Microcontroller
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Microcontroller Kit
Microcontroller Kit is designed for training in Microcontroller
programming.
MINI18 PIC Training Kit is used here to design, test and
develop PIC microcontroller programming.
This Kit consists of Programmer and Application Circuit in
one unit.
• uses PIC16F88 microcontroller.
• has many applications in addition to the low price that is
suitable for education and robotic competition.
• has 14 pin I/O and also ADC and PWM functions.
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Microcontroller Kit Circuit
Application circuit
Programmer Circuit
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PIC 16F88 Microcontroller Kit
Application
socket
Programmer
socket
Programming circuit can be connected directly to serial
port of PC or using extension cable.
In the application circuit above, there are 2 input
switches, 6 LEDs, 1 LDR sensor and 1 Buzzer Alarm.
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Kit Connection to PC
This is used when downloading the program from PC to PIC.
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Kit Connection to PC
Serial extension cable can also be used.
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Transfer from Programmer to Application
After the programming download is completed, The PIC can be
removed from programmer socket to application socket.
Be careful since the PINs are fragile.
Then connect 9V supply to the terminal and switch ON test
the circuit.
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Basic Command in C
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Statement/Comment
Comment is made only to help the programmer as
explanation, it will not be executed by computer.
Using // for one line statement
or /*.....statement........*/ for one paragraph statement or
comment.
Example:
PORTB = 0;
//Setting all values of PORTB = 0
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Programming Structure
For each program, it must begin with command:
void main()
Each command line ends with semicolon:
;
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Operator
Assignment operator
It uses (“=”). example:
input = 80; //variable “input” is equal to 80
A = x * y; //variable “A” has value of multiplicaion between x and y.
Arithmatic operator
* : multiplication
/ : division
+ : addition
- : subtraction
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Operator (contd.)
Relational Operator
<
<=
>
>=
==
!=
less than
Less than or equal to
Greater than
Greater than or equal to
Equal to
Not equal to
Logic Operator
&&
||
!
Logic AND
Logic OR
Logic NOT
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Conditions
if…. and if….else
In the structure if.....else the are at least two statement. If the given
expression is true then statement-1 will be executed, otherwise if
the given expression is false then stetement2 will be executed. It
has common form as:
If (condition) {…..}
if(condition){statement-1}
else {statement-2 }
Example:
if (m == 1) {x = x + 20} else {y = y – 10};
// If m=1 then the new value of x is x+20, otherwise the new value of y is y-10.
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Looping
Looping with do..while
The looping process will continue if the given condition is true otherwise
looping will be stopped.
do {statement} while (condition);
Example:
int s, i;
s = i = 0;
do
{
s = s + 2;
i = i + 1;
}
while (i < 7);
//This will add value of variable s by 2 in 7 times; at the end the value of s will be 14.
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PIN and PORT Assignment
Byte Mapping in PORT
PORTB has 8 pins: B0, B1, B2, B3, B4, B5, B6, B7
With the order from right:
PORTB
=
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0
For example to set only pin RB2 and RB4 to high
state 1 (ON), the command is:
PORTB=0b00010100;
PORTB
=
0
0
0
1
0
1
0
0
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PIN and PORT Assignment
PIN or PORT values can be determined per PIN
or per PORT.
The command below are the same:
PORTB.F0 = 0;
PORTB.F1 = 0;
PORTB.F2 = 1;
PORTB.F3 = 0;
PORTB.F4 = 1;
PORTB.F5 = 1;
PORTB.F6 = 0;
PORTB.F7 = 1;
Per PIN
Same as:
PORTB= 0b10110100;
Per PORT
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Per PORT Command
Per PORT command can be in decimal, binary or
hexadecimal form.
Bilangan
Operator
Example
Value
Binary
0b
PORTB=0b00111111;
Value of PORT B: B0=1,
B1=1, B2=1, B3=1,
B4=1, B5=1, B6=0,
B7=0
Hexadecimal
0x
PORTB=0x0F ;
0F is equivalent to
00001111, that means
PORT B value: B0=1,
B1=1, B2=1,
B3=1,B4=0,B5=0, B6=0,
B7=0
PORTB =12 ;
Decimal 12 is equal to
00001100 in binary, thus
PORT B: B0=0,B1=0,
B2=1, B3=1,
B4=0,B5=0, B6=0, B7=0
Decimal
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Defining Input or Output PORT/PIN
To assign a PORT or PIN as Input or Output, command
TRIS is assigned:
PORTB as output
TRISB = 0 ; //same as 0b00000000
PORTB as input
TRISB = 0b11111111;
Only PIN B1 as output
TRISB.F1 = 0;
Only PIN B3 as input
TRISB.F3 = 1;
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Digital Input Checking
To check digital input to the PIC (0V or 5 V), this command can
be given:
If (expression) {statement…}
Example:
If Port RA1 = 5V then Output of Port RB1 will be 1 (5V).
If (PORTA.F1 == 1) {PORTB.F1=1}
To delay the next command to be executed, the command is:
Delay_ms(1000); //To delay the next command by 1s (1000 ms)
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PIN Setting as Digital or Analog
Command ANSEL can only be used by PIN
with label AN.
For example AN6 (Pin B7) will be set as
analog, thus the command:
ANSEL.F6=1;
If let say PIN AN3 (Pin A2) is set to be digital:
ANSEL.F3=0;
For all PINs AN to be digital input:
ANSEL=0b0000000;
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ADC Activation
To activate function conversion from analog to Digital (ADC), if
PIN AN (Input Analog) is used. The command is ADCON0.
To make the ADC function active:
ADCON0 = 1;
To make ADC function inactive, the command is:
ADCON0 = 0;
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First Project: Exercise
In this first project, we will try to turn
on LED with the sequence as
follows:
• All 6 LEDs connected to PORT B
(RB0 to RB5) are ON in the first 1s.
• In the next 1s, only LED on PORT
B0, B2, B4 are ON (or Red-GreenYellow).
• Then, in the next 1s after that, only
LED on PORT B1, B3 and B5 are
ON (Yellow-Green-Red).
• The process is repeated to
sequence 1.
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First Project: Algorithm
For this project, the algorithm is as follows:
1. Define PORT that will be used as output.
2. Define initial value of PORT.
3. Start the program.
4. Set output HIGH (1) for PIN on PORT B0-B5
5. Delay for 1s (1000ms).
6. Set output HIGH for PORT B0, B2, B4 only, the rest are LOW.
7. Delay for 1s (1000ms).
8. Set output HIGH for PORT B1, B3 and B5, the others are LOW.
9. Delay for 1s (1000ms).
10.Repeat to number 3.
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First Project: Programming
Programming is done using MicroC software.
Click ProjectNew, then specify
the name of the project and
folder location.
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Write the project name as “First_project”
Specify the Project Path to save the files.
Discription, we can leave it as blank (optional).
Select Device, select PIC16F88.
In Clock, write 20.000000 (20 MHz).
Click default to use default settings. Then click OK.
Then, MikroC compiler will
prepare the project file and
displays the window editor to
write the source code
program.
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/* Name: First_project written in C
Connection: LED B0-Red, B1-Yel, B2-Gre, B3-Red, B4-Yel, B5-Gre
B6_SW1, B7-SW2
A1=Buzzer, A0=LDR */
void main()
{
PORTB = 0;
//Initial setting PORTB=0
TRISB = 0;
//Set PORTB as Output
do
{
PORTB = 0b00111111; //output PORTB in binary 00111111
Delay_ms(1000);
PORTB = 0b00101010; //output PORTB in binary 00101010
Delay_ms(1000);
PORTB = 0b00010101; // output PORTB in binary 00010101
Delay_ms(1000);
}
while(1) ;
}
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Command Definition
Command
Explanation
void main()
To begin the main program
{or }
The bracket is used only to identify command into
the blocks. To make the program easy to undertand.
// or /*…..*/
Comment that will not be executed by computer.
// is for one line statement.
/* in the beginning of paragraph and */ in the end of
paragraph.
PORTB = 0b00000000;
Set initial value PORTB=0.
TRISB = 0b00000000;
Set PORTB as Output.
Example: TRISB = 0x00 is also to set PORT B
as output and TRISB = 0b11111111 is to set
PORT B as input.
Partly input and output can also be set, for
example: TRISA= 0b00001111 means PORTA
pin A0,A1,A2,A3 as input (since set to 1) and
pin A4,A5,A6,A7 as output (since set to 0).
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Command Definition (contd.)
do… while(1);
To set the loop without ending. While (1) if
the condition is TRUE or 1, then repeat to do
again.
PORTB = 0b00111111;
On PORTB the output is given as:
B0=1,B1=1,B2=1,B3=1,B4=1,B5=1, B6=0,
B7=0. (bit sequence from right)
Delay_ms(1000);
To pause the next exceution by 1000ms or 1s.
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Program Compiling
After the program is wriiten in the editor, then save
Then click Compile Icon
the file.
or build project.
It takes a while for MikroC to compile
the program, a .hex file will be crated.
This .hex file will be transferred into
the Microcontroller.
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Transferring Hex File to PIC
To transfer or download the .hex file to PIC, firstly open WinPIC800 software.
Then plug the PIC Kit board into Serial Port/COM1 in the PC. The PIC must be
connected to Programmer circuit to download .hex file.
Select PIC 16F88 in pull down as shown by figure.
Then click
to check the serial port connection of the PIC board to the PC.
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Then click icon “erase all”
to delete all previous program existing in the PIC.
Then click open file icon
PIC.
to select .hex file that will be downloaded to the
Then click
to transfer the hex file of your project to PIC.
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After the hex file has been transferred, then unplug the PIC board
from the serial port of the PC. And remove the IC to application
circuit. Connect 9v supply to the terminal and press switch ON.
We can see the LEDs are ON according to the programmed
sequence.
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