Chapter2 2014 cont

MICROCONTROLLER 16F877A

USING C LANGUAGE(MIKROC VER. 8.0)

CONT…

MICROCONTROLLER

• The microprocessor can provide, in a simplified form, all the main elements of the conventional microprocessor system on one chip.

• Used to control a small system.

INPUT /OUTPUT PORTS

• Each microcontroller has one or more registers (called ports) connected to the microcontroller pins.

• Why input/output? Because you can change a pin function as you wish.

• For example, suppose you want your device to turn on/off three signal LEDs and simultaneously monitor the logic state of five sensors or push buttons.

• Some of the ports need to be configured so that there are three outputs (connected to LEDs) and five inputs (connected to sensors).

• It is simply performed by software, which means that a pin function can be changed during operation.

INPUT /OUTPUT PORTS

• For practical reasons, many I/O pins have two or three functions. If a pin is used as any other function, it may not be used as a general purpose input/output pin; and

• Every port has the corresponding TRIS register: TRISA, TRISB, TRISC etc. which determines performance, but not the contents of the port bits.

By clearing some bit of the TRIS register (bit=0), the corresponding port pin is configured as output. Similarly, by setting some bit of the TRIS register (bit=1), the corresponding port pin is configured as input. This rule is easy to remember 0 = Output, 1 = Input.

In order pins’ operation can match internal 8-bit organization, all of them are, similar to registers, grouped into five so called ports denoted by A, B, C, D and E. They all have several features in common:

PROGRAMMING LANGUAGE

The microcontroller executes the program loaded in its Flash memory.

A specialized program in a PC called compiler is in charge of compiling program into machine language (hex file).

The main advantage of C languages is simplicity of program writing.

A rough illustration of what is going on during the process of compiling the program from higher to lower programming language.

Simplify of C compared to

assembly

Same program compiled into assembly code

THE BASICS OF C PROGRAMMING LANGUAGE

/* Text between these signs is not compiled into executable code and represents a comment. */

//This sign is used for short comments//within one program line

MikroC Ver. 8.0 First Look

• mikroC for PIC is a full-featured ANSI C compiler for PIC devices from Microchip®.

• It is the best solution for developing code for PIC devices. It features intuitive IDE, powerful compiler with advanced optimizations, lots of hardware and software libraries, and additional tools that will help you in your work.

• Compiler comes with comprehensive Help file and lots of ready-to-use examples designed to get you started in no time. Press F1 to get help.

Case 1 : Turn On LED

Special Function RegistersSpecial Function Registers

InfoInfo

TRISB

xxxxxxxx

PORTB

xxxxxxxx

void main()

{

TRISB = 0b00000000;

PORTB = 0b00000001;

}

C programming code to turn the LED on. LED is connected to PORTB bit 0



InfoInfo

TRISB

xxxxxxxx

PORTB

xxxxxxxx

void main()

{

TRISB = 0b00000000;

PORTB = 0b00000001;

}

As soon as the microcontroller is turned on, it will execute the main() function



InfoInfo

TRISB

00000000

PORTB

xxxxxxxx

void main()

{

TRISB = 0b00000000;

PORTB = 0b00000001;

}

Set all bits TRISB register to 0. This makes the whole bit of PORTB as output.

* 0 = Output, 1 = Input



InfoInfo

TRISB

00000000

PORTB

00000001

void main()

{

TRISB = 0b00000000;

PORTB = 0b00000001;

}

• Set binary value 00000001 to PORTB.• LED D1 lights up.

* 0 = 0Volt, 1 = 5Volt

Red indicator: 5V = Digital 1

Blue indicator: 0V = Digital 0



InfoInfo

TRISB

00000000

PORTB

00000001

void main()

{

TRISB = 0b00000000;

PORTB = 0b00000001;

}

• Program END• LED D1 light up forever•Code execution ended.


void main()

{

TRISB = 0b00000000;

PORTB = 0b00000001;

}

Various styles of code programming. Each of them produce the same output.

void main()

{

TRISB.F0 = 0; //Only bit 0 set as output

PORTB.F0 = 1;

}

=

#define LED PORTB.F0 //LED at PORTB bit 0

void main()

{

TRISB = 0b00000000;

LED = 1;

}

=

#define LED PORTB

void main()

{

TRISB = 0b00000000;

LED = 0b00000001;

}

=

Software Delay

Software delay is a special function to make the flow of the system hold/pause to specific times. The delay can be set in microsecond and millisecond.

• Delay_us(10); /* 10 microseconds pause */

• Delay_ms(1000); /* 1000ms ~ 1 second pause */

List of delay function codes in MikroC:

Case 2 : LED Blinking


InfoInfo

#define LEDS PORTB

main()

{

TRISB = 0b00000000; //All PORTB bits are output

LEDS = 0b00001010; //D1 and D2 light up.

Delay_ms(1000); //Pause for 1 sec

LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

xxxxxxxx

PORTB

xxxxxxxx

•Blink the LED1 and LED2 for 1 second•LED1 at PORTB bit 1•LED2 at PORTB bit 3

20Mhz



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

xxxxxxxx

PORTB

xxxxxxxx

•Define PORTB as LEDS

20Mhz



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

xxxxxxxx

PORTB

xxxxxxxx

•Execute the main() function

20Mhz



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

00000000

PORTB

xxxxxxxx

Set all bits TRISB register to 0. This makes the whole bit of PORTB as output.

* 0 = Output, 1 = Input

20Mhz



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

}20Mhz

TRISB

00000000

PORTB

00001010

LED1 = ONLED2 = ON

* 0 = 0V, 1 = 5V

20Mhz



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

}20Mhz

TRISB

00000000

PORTB

00001010

LED1 and LED2 still ONand wait for 1 second

20Mhz



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

00000000

PORTB

00000000

20Mhz

LED1 = OFFLED2 = OFF

* 0 = 0V, 1 = 5V



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

00000000

PORTB

00000000

20Mhz

LED1 and LED2 still OFF and wait for 1 second



InfoInfo

#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

} TRISB

00000000

PORTB

00000000

20Mhz

• After wait for 1 second the program END.• LED1 and LED2 not blink anymore• The LEDs only ON and OFF one time.

Code execution ended


#define LEDS PORTB

main()

{




LEDS = 0b00000000;

Delay_ms(1000);

}

Case 3 : LED Always Blinking


InfoInfo

#define LEDS PORTB

Void main()

{


while(1) // endless loop

{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

xxxxxxxx

PORTB

xxxxxxxx

20Mhz

• Make LED1 and LED2 blinking forever.

From the previous code, the LEDs only blink for 1 time. To make the LEDs always blink, add “while(1)” command to make the program looping forever.



InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

xxxxxxxx

PORTB

xxxxxxxx

20Mhz

•Define PORTB as LEDS




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

xxxxxxxx

PORTB

xxxxxxxx

20Mhz

Execute the main() function




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

xxxxxxxx

20Mhz

Set all PORTB bits as output




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

xxxxxxxx

20Mhz

The condition of while is always 1 (true). So this is an infinite loop.




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

00001010

20Mhz

LED1 = ONLED2 = ON

* 0 = 0V, 1 = 5V

20Mhz




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

00001010

20Mhz

LED1 and LED2 still ONand wait for 1 second

20Mhz




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

00000000

20Mhz20Mhz

LED1 = OFFLED2 = OFF

* 0 = 0V, 1 = 5V




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

00000000

20Mhz20Mhz

Wait for 1 second




InfoInfo

#define LEDS PORTB

main()

{



{



LEDS = 0b00000000;

Delay_ms(1000);

}

}

TRISB

00000000

PORTB

00001010


20Mhz

• After wait for 1 second, program goes to loop and start

again to light up the LEDs.

• As a result, the two led flashes all the time.

• The use of while(1) is essential for the continuation of the program.

Case 3 : LED Always Blinking“Animated Gif”



#define LEDS PORTBmain(){ TRISB = 0b00000000; //All PORTB bits are output while(1) // endless loop { LEDS = 0b00001010; //D1 and D2 light up. Delay_ms(1000); //Pause for 1 sec LEDS = 0b00000000; Delay_ms(1000); //Pause for 1 sec }}

#define LED1 PORTB.F1#define LED2 PORTB.F3main(){ TRISB = 0b00000000; //All PORTB bits are output while(1) // endless loop { LED1 = 1; //D1 ON LED2 = 1; //D2 ON Delay_ms(1000); //Pause for 1 sec LED1 = 0; //D1 OFF LED2 = 0; //D2 OFF Delay_ms(1000); //Pause for 1 sec }}

=

Case 4 : LED Running Light

“Animated Gif”

• LED in running light with 1 second delay.

InfoInfo

Case 5 : LED and Button


InfoInfo

TRISC

xxxxxxxx

PORTC

xxxxxxxx

• Press the button to light up LED and LED off when release the button.

B1 (Input) D1 (Output)

1 (5V) 0 (0V)

0 (0V) 1 (5V)

void main(){

TRISC = 0b00100000; //Bit 5 PORTC set to Input, the // rest as output

PORTC = 0b00000000; //Clear all bits of PORTC

while(1) //infinite loop

{

if (PORTC.F5 == 0) //if got 0 or 0V (button1 pressed)

{

PORTC.F2 = 1; //LED1 ON

}

else // got 1 or 5V (button1 not pressed)

{

PORTC.F2 = 0; //LED1 OFF

}

}

}



InfoInfo

TRISC

00100000

PORTC

xx1xxxxx

void main(){




{


{


}


{


}

}

}

Set PORTC bit 5 as input, the rest as output



InfoInfo

TRISC

00100000

PORTC

00100000

void main(){




{


{


}


{


}

}

}

Clear all bits at PORTC



InfoInfo

TRISC

00100000

PORTC

00100000

void main(){




{


{


}


{


}

}

}

The condition of while is always 1 (true). So this is an infinite loop.



InfoInfo

TRISC

00100000

PORTC

00100000

void main(){




{


{


}


{


}

}

}

•Check if input at bit 5 get 0 or 1, in this case button is not press. So bit 5 got 1.

Digital 1 = 5Volt



InfoInfo

TRISC

00100000

PORTC

00100000

void main(){




{


{


}


{


}

}

}

•The if command got false signal, so jump to else.



InfoInfo

TRISC

00100000

PORTC

00100000

void main(){




{


{


}


{


}

}

}

•Clear bit 2 (LED off)



InfoInfo

TRISC

00100000

PORTC

00000000

void main(){




{


{


}


{


}

}

}

•Program goes to loop and start again to check the button•This time button is pressed and bit 5 got 0 (TRUE signal)

Digital 0 = 0Volt



InfoInfo

TRISC

00100000

PORTC

00000100

void main(){




{


{


}


{


}

}

}

•PIC send 5Volt to PORTC bit 5•D1 light up.



InfoInfo

TRISC

00100000

PORTC

00000100

void main(){




{


{


}


{


}

}

}

•Program will goes to loop and start again to check the button•This process is repeated like previous.

Case 5 : LED and Button“Animated Gif”

* LED is always ON as long as the button is pressed and OFF when the button is released.


void main(){ TRISC = 0b00100000; //Bit 5 PORTC set to Input, //the rest as output PORTC = 0b00000000; //Clear all bits of PORTC while(1) //infinite loop { if (PORTC.F5 == 0) //if got 0 or 0V (button is pressed) { PORTC.F2 = 1; //LED1 ON } else // got 1 or 5V (button is not pressed) { PORTC.F2 = 0; //LED1 OFF } }}

#define BUTTON PORTC.F5#define LED1 PORTC.F2void main(){ TRISC = 0b00100000; //Bit 5 PORTC set to Input, //the rest as output PORTC = 0b00000000; //Clear all bits of PORTC while(1) //infinite loop { if (BUTTON==0) //if got 0 or 0V (button is pressed) { LED1 = 1; //LED1 ON } else // got 1 or 5V (button is not pressed) { LED1 = 0; //LED1 OFF } }}

=


Case 6 : LED and Button Method 2

InfoInfo

•In this example, LED will emit light for 1 second only when button is released. After that LED will OFF.•Unlike the previous methods ,when a button is pressed, the LED lights up quickly.

Case 7 : 2 LEDs and 2 Buttons

InfoInfo

•In this example, there are two buttons that use different circuits. B1 and B2 respectively give the values of 0 and 1 when pressed.

“Animated Gif”

Case 8 : Relay#define RELAY PORTC.F5 //Relay at PORTC bit 5#define LED PORTB.F0 //LED1 at PORTB bit 0#define BON PORTA.F0 //Button ON at PORTA bit 0#define BOFF PORTA.F2 //Button OFF at PORTA bit 2void main(){ TRISA = 0b11111111; //Set all bits of PORTA as input ADCON1 = 0b00000110; //Set PORTA as digital input //ADCON1 is only for PORTA TRISB = 0b00000000; //Set all bits of PORTB as output PORTB = 0b00000000; //Clear all bits of PORTB TRISC = 0b00000000; //Set all bits of PORTC as output PORTC = 0b00000000; //Clear all bits of PORTC

while(1) //infinite loop { if (BON == 1) //if Button ON is pressed { RELAY = 1; LED = 1; } if (BOFF == 1) //if Button OFF is pressed { RELAY = 0; LED = 0; } } //end of while} //end of main()

“Animated Gif”

Info: Two buttons to activate and deactivate relay and LED. Relay connected to 12V lamp.

#define sevensegment PORTBvoid main(){ TRISB = 0b00000000; //PORTB as output PORTB = 0b00000000; //Clear PORTB while(1) //infinite loop { //Using dec2bcd.Convert 8 bit decimal to binary code decimal //example: dec2bcd(13) = 00010011, dec2bcd(88) = 10001000 sevensegment = dec2bcd(1); //binary code decimal of no. 1 (00000001) Delay_ms(1000); sevensegment = dec2bcd(2); //binary code decimal of no. 2 (00000010) Delay_ms(1000); sevensegment = dec2bcd(3); //binary code decimal of no. 3 (00000011) Delay_ms(1000); }}

Case 9 : Seven Segment with decoder

“Animated Gif”


=

Case 9 : Seven Segment with decoder

#define sevensegment PORTBvoid main(){ TRISB = 0b00000000; //PORTB as output PORTB = 0b00000000; //Clear PORTB while(1) //infinite loop { //Using dec2bcd.Convert 8 bit decimal to binary code decimal //example: dec2bcd(13) = 00010011, dec2bcd(88) = 10001000 sevensegment = dec2bcd(1); //binary code decimal of no. 1 (00000001) Delay_ms(1000); sevensegment = dec2bcd(2); //binary code decimal of no. 2 (00000010) Delay_ms(1000); sevensegment = dec2bcd(3); //binary code decimal of no. 3 (00000011) Delay_ms(1000); }}

#define sevensegment PORTBint i;void main(){ TRISB = 0b00000000; //PORTB as output PORTB = 0b00000000; //Clear PORTB while(1) //infinite loop { for (i=1;i<=3;i++) //using “for loop” { sevensegment = dec2bcd(i); Delay_ms(1000); } }}

Interrupt

Engineering

Chapter2 2014 cont