Programming PIC16F877A

Using CCS C Compiler and US-

Burn

Why Use C for Embedded Programming?

1. Portable code can be retargeted to different processors

2. Clarity C is easier to understand than assembly

3. Compilers produce code that is close to manually-tweaked assembly language in both code size and performance

From .c to .hex

C Compilers for Embedded Systems

CCS C Compiler HI TECH Compiler

CCS vs. HI TECH

The CCS Compiler has an extensive range of inbuilt functions Save time and speed up the learning process

The HI TECH Compiler is based towards those who are following a company policy specifying the ANSI standard with hardware functions sometimes resembling Assembler more than C

Installing CCS C Compiler IDE

Copy CCS C directory to your hard drive Run pcwhupd.exe (in this directory) Copy the following files to installed directory

: PCM.CRG for 16-bit PIC , PCH.CRG, PCB.CRG

Run Patch.exe file Run Pcw.exe file

Installing US-Burn

1. Copy USB burn driver directory to your harddrive

2. Plug USB cable (connected to the USB port of SaigonTech PIC Board) to computer USB port

3. Turn on the power switch on the PIC board (see the next slides)

\USB burn driver

Click the Browse button to select the driver folder

Succefull installation announce

Do the steps 2 and 3 for other USB ports.

A Sample C Program:

Blinking 8 LEDs

Program Description

Make LEDs on PORTB blink every second

Cable Wiring

Use a 8 pin ribbon cable to connect PICs jumpers B0 B7 to LEDs jumpers L0 L7

Electronic Circuit

Writing Program in PCW C

Compiler IDE

Creating a .c File

Creating a .c File

File name: Blink8LEDs Choose the path Click Save

Editing Blink8LEDs.c

Compiling a C Program

Using US-Burn to Load a .hex

File to the PIC

Put 16F877A in the USB Programmer socket (pay attention to the PIC direction on the socket, otherwise you will damage the PIC)

Plug the USB cable to the PC and to the PIC board

Turn on the power switch of PIC Board Run Usburn14.exe

Microcontroller Setting

Run program on the board

Turn off the power switch on the PIC board Put the programmed PIC in the Run socket

on the board (pay attention to the PIC direction on the socket, otherwise you will damage the PIC)

Turn on the power switch on the PIC board to see the LEDs blink.

Summary of the

Development

Process

PIC C

PIC C

PIC C

Discussion

Look at an Alternative of BlinkLEDs.c

Is this listing better than the previous one? Why?

One of the Most Important Skills in

Programming

Reuse

PIC16F877A

5/6 Programming pins8 10-bit A/D channels2 Oscillator Inputs2 RS-232 inputs33 I/O ports2 PWM channels

The PIC16F877A

PIC: Peripheral Interface Controller

Pin Functions

MCLR to reset the PIC VDD power supply VSS ground OSC1, OSC2 connect to oscillator The pins having the notation R can all be

used as digital inputs or outputs The pins that are labeled as AN can be used

as analog inputs The pins CCP1 and CCP2 are used for PWM

Exercise

1. Delete NOLVP from #fuses and rerun the program. What is the effect of this action?

2. Instead of using the PORTB, use PORTC to rewrite the example

Try to use NOLVP and without it

Why is NOLVP Needed?

In Single Supply Programming or Low Voltage Programming mode (using single voltage VDD 5V to programming): The LVP bit will be set Pin B3 will have PGM function B3 is cleared

To make RB3 become a normal I/O pin, LVP has to be disabled #fuses NOLVP

Exercise

Instead of using the PORTB, use PORTA to rewrite the example

More Details on PORTA In the PIC16 series Port A is the analog port

connected to the analog to digital converters By default this port is configured as analog You will not be able to output or input data reliably

on Port A until you configure it as a digital portPin RA4

PIC 16F877A

Cant work

R

VDD

How to Make RA4 Work Properly

RA4 is made to be an open-drain output A pull-up resistor is needed to make it work

properly

Pin RA4

PIC 16F877A

Cant work R

VDD

Pin RA4

PIC 16F877A

Open-drain output

Pull-up Resistor

References

Microcontroller. http://www.electronics.netmyne.com/microcontroller.html

Programming PIC Microcontrollers in BASIC. mikroElektronika 1998 2004. http://www.mikroelektronika.co.yu/english/product/books/picbasicbook/00.htm#preface

http://www.picvietnam.com/forum//showthread.php?t=357

PICC. An introduction to programming the Microchip PIC in C. Nigel Gardner. Bluebird Electronics 1998