Feb. 2014

1

2 Embedded Systems Lab

Grading Policy

- MID Term Exam 20

(10 practical – 10 Theoretical)

- Final Term Exam 30

- Reports 20

- Project 15

- Quizzes 5

- Attendance+ lab-work 10

Total 100

3 Embedded Systems Lab

Objectives

- To be familiar with microcontrollers, PIC184550 microcontroller.

- To be familiar with some software tools like MPLAB, mikroBasic, PROTEUS

and QL_PROGen knowing their components and some features.

- To know how to make a project using MPLAB and mikroBasic and then get

the hex file of the software program of the project.

- To know how to simulate your program using PROTEUS.

- To know how to load the code into microcontroller using hardware

components.

Introduction

A microcontroller (or MCU) is a computer-on-a-chip. It is a type of

microprocessor emphasizing self-sufficiency and cost-effectiveness, in

contrast to a general-purpose microprocessor (the kind used in a PC).

A microcontroller is a single integrated circuit, commonly with the following

features:

- Central processing unit - ranging from small and simple 4-bit processors to

sophisticated 32- or 64-bit processors

- Input/output interfaces such as serial ports (UARTs)

- Peripherals such as timers and watchdog

- RAM for data storage

- ROM, EPROM, EEPROM or Flash memory for program storage

- Clock generator - often an oscillator for a quartz timing crystal, resonator or

RC circuit

- Many include analog-to-digital converters

Introduction to Software Tools

4 Embedded Systems Lab

Microcontroller versus Microprocessor

A microcontroller differs from a microprocessor in many ways. The first and

most important difference is its functionality. In order that the

microprocessor may be used, other components such as memory must be

added to it. Even though the microprocessors are considered to be powerful

computing machines, their weak point is that they are not adjusted to

communicating to peripheral equipment. On the other hand, the

microcontroller is designed to be all of that in one. No other specialized

external components are needed for its application because all necessary

circuits are already built into it.

Input/output Ports

Each microcontroller has one or more registers (called a “port”) connected to

the microcontroller pins. Every pin is one bit << PIC has many ports (general

function register: a, b, c, d, e) << Ports are used for inputting and outputting

data (ex: input by button, output by LED) << Every port is connected with

special function register called Tris << Tris is used to make configuration for

the port to indicate if it is input (tris=1) or output (tris=0).

5 Embedded Systems Lab

For example:

To configure port B as an input we but Trisb=11111111 and read the value

form portB and to configure the first pin in port C as output we put

Trisc=11111110. You will get used to this during the lab.

for tris register 1 is input and 0 is output. Remember:

1nput 0utput

Memory Unit

Memory is part of the microcontroller used for data storage.

1. Read Only Memory (ROM)

ROM (Read Only Memory) is used to permanently save the program being

executed. The size of a program that can be written depends on the size of

this memory.

2. Flash memory

The contents of this memory can be written and cleared practically an

unlimited number of times, the microcontrollers with Flash ROM are ideal for

learning, experimentation and small-scale manufacture.

3. Random Access Memory (RAM)

Once the power supply is off the contents of RAM (Random Access Memory)

is cleared. It is used for temporary storing data and intermediate results

created and used during the operation of the microcontroller.

4. Electrically Erasable Programmable ROM (EEPROM)

The contents of the EEPROM may be changed during operation (similar to

RAM), but remains permanently saved even upon the power supply goes off

(similar to ROM). Accordingly, an EEPROM is often used to store values,

created during operation, which must be permanently saved. For example, if

6 Embedded Systems Lab

you design an electronic lock or an alarm, it would be great to enable the user

to create and enter a password, but useless if it is lost every time the power

supply goes off. The ideal solution is the microcontroller with an embedded

EEPROM.

Central Processor Unit (CPU)

As its name suggests, this is a unit which monitors and controls all processes

inside the microcontroller. It consists of several smaller subunits like

Instruction Decoder, Arithmetical Logical Unit (ALU) and Accumulator.

PIC Microcontrollers

PIC (Peripheral Interface Controller) microcontrollers designed by Microchip

Technology are likely the right choice for you if you are a beginner.

PIC18F4550

This is the microcontroller we are going to use during our lab.

- High Performance RISC CPU.

- Operating Frequency: DC – 48 MHz

- Linear program memory addressing to 32 Kbytes.

- Can store up to 16,384 single-word instructions.

- Linear data memory addressing to 2 Kbytes.

- 256 bytes EEPROM memory.

- Five bidirectional I/O Ports: A, B, C, D, E.

- Three independent Timers/Counters & Watch-dog timer.

- Serial Communications:

o Enhanced USART Module, Supports RS-485, RS-232.

o Master Synchronous Serial Port (MSSP): supports SPI and I2C mode.

7 Embedded Systems Lab

- Streaming Parallel Port (SPP).

- Incorporate a fully featured Universal Serial Bus communications module

that is

- Compliant with the USB Specification Revision 2.0.

- Compatible 10-bit Analog-to-Digital Converter: 13 input channels.

Pin Diagram

Datasheet link

ww1.microchip.com/downloads/en/devicedoc/39632e.pdf

Pin Diagram clear photo

http://www.mediafire.com/view/?nd3hzb6gz7jmb25

8 Embedded Systems Lab

Programs used

These programs are the backbone of the microprocessor and microcontroller

based systems; since using MPLAB we can build the software of the project

using C or Assembly language, and then we can simulate the project virtually

using PROTEUS, finally we can download the program on the

microcontroller and see the results practically using WinPic. So this

experiment includes all the knowledge the student will need to get started to

these programs.

MPLAB Program

MPLAB is a software program that runs on your PC to provide a development

environment for your embedded system design. In other words it is a

Windows program package that makes writing and developing a program

easier. It could best be described as developing environment for a standard

program language that is intended for programming microcontrollers.

Get started to MPLAB

- From the project menu choose project wizard.

- Choose PIC18F4550.

- Browse and name the project.

- From view menu choose project; to view the project

- Add P18F4550.inc, P18F4550.lkr files to project.

- At path: <<Program Files<<MicroChip\MPASM Suite (or \LKR)

(You can copy this file into the path in LKR folder to aviod errors << add it to project)

- To write your code, open new file from here or (file-new), write your code,

save it with ex: Name.asm. (don’t forget .asm !!)

- Then add a file to the source files by right clicking on source files, and choose

add files and then name the file any Name.asm.

9 Embedded Systems Lab

An assembler is a program that converts source-code programs written in

assembly language into object files in machine language.

A linker is a program that combines your program’s object file created by

the assembler with other object files and link libraries, and produces a

single executable program.

Steps to Create a Program

Files Used By MPLAB IDE

.asm: Assembly language source file – MPASM assembler

.hex: Machine code in hexadecimal format file

.inc: Assembly language include file – Microchip assemblers

.lkr: Linker script file – MPLINK linker

For complete description about MPLAB see MPLAB_User_Guide

10 Embedded Systems Lab

Program main structure

Make BuildAll

include<p18f4550.inc>: similar to import

global main : start to execute from „main‟ label

org 0x2A : address of main

main : start the code from here

movlw 0x00 : move literal(value) to work register (wreg): wreg=0

movwf TRISB : move from wreg to file register :portb-output

movlw 0x8A : wreg=8A

movwf PORTB : portb=8A

end : end of the main code

Description

11 Embedded Systems Lab

In order to make writing code easier, you can disable case sensitivity:

Project << Build option << project << MPASM Assembler << tick ‘Disable case

sensitivity’.

- Avoid some mistakes in your work: don’t change the name of file when you

add it << don’t put the file in Arabic words path.

MikroBasic

We will be using also Mikrobasic language, for more details you have to check

the language reference for MikroBasic

<< Starting new MikroBasic Project

Note

Avoid !!

12 Embedded Systems Lab

Enter a name and choose a path to your project and then choose you PIC

device –for our lab it will be PIC18F4550- and if you use an external oscillator

then you have to specify its value –we will use a crystal of 8MHz value-.

Now you have to check some flags in the device –we will talk about them

later- but for now just check:

Save the scheme with a

name in order to avoid

searching again for the

flags.

13 Embedded Systems Lab

Program main structure

program Progname

‘function declaration

main:

‘variable declaration

adcon1 = adcon1 or 0x0f 'convert input to digital

‘tris configuration

while true

‘program body

wend

end.

PROTEUS Program

Proteus contains everything you need to develop; test and virtually

prototype your embedded system designs based around the Microchip

Technologies™ PIC 18 series of microcontrollers. This design synergy allows

engineers to evolve their projects more quickly, empowering them with the

flexibility to make hardware or firmware changes at will and reducing the

time to market. Proteus VSM models will fundamentally work with the exact

same HEX file as you would program the physical device with, binary files

(i.e. Intel or Motorola Hex files) produced by any assembler or compiler.

How to setup PROTEUS?

1. Open Labcenter.Proteus.Professional.v7.10 folder and run the setup.

2. Press next until you reach the window which asks for the key.

3. From browse for key; browse until you reach the same folder where the

setup exists, and then open the crack folder.

4. Then click on Grassington North Yorkshire.lxk and then press install.

5. Then choose yes and close the window, after that browse and install the

program.

6. After that run the patch LXK Proteus 7.10 which exists in the Crack folder

as an administrator, then click update.

14 Embedded Systems Lab

Get started to PROTEUS

1. From start menu chose the PROTEUS, and then chose ISIS (blue).

2. To get a part click on Devices (P) … some needed components are here:

Part Keyword

Microcontroller PIC18F4550

Resistor res (change value!)

Button button or push

LEDs led-

3. Write the name of the PIC18F4550.

Show your

hardware

parts

Add new

parts

Show terminals:

VDD and GND

15 Embedded Systems Lab

Don’t forget to connect a VDD to the MasterClear Pin (pin#1) in order for the

Microcontroller to work.

To install your program to the Microcontroller: double-click on it and choose the

.hex file then assign the right 8MHz clock because we use a crystal of 8MHz

16 Embedded Systems Lab

Now you can run the simulation

P Hardware work

Basic hardware connections

Pin# Pin Name What to connect

1 Active low Mater clear +5V

11 VDD +5V

12 VSS Ground

13 OSC1 Crystal

14 OSC2 Crystal

31 VSS Ground

32 VDD +5V

17 Embedded Systems Lab

QL_PROGen (used to program the PIC)

Put the PIC at the right place in programmer

Connect the programmer to the computer

Chip select << Port select << Load (.hex file): when ‘Ready’ appears … your

work seems to be correct … then click Program..

18 Embedded Systems Lab

“Programming complete“ tells you that PIC has been programmed

successfully and ready to be used at your kit

19 Embedded Systems Lab

<< Proteus circuit connection is shown at the following page >>

For hardware connection:

- Load the code at the pic using Programmer (connect it to the computer <<put

the pic at the correct position << load the code).

- Put the pic at the suitable place at the kit and use wires to represents the

needed connection in order to show the output using LEDs.

- Don’t forget to use a power source to activate your work.

1. Write an assembly language program that load “0x03” to

port B.

2. Simulate the circuit using Proteus ISIS program.

3. Connect the circuit at the hardware kit.

4. Connect the circuit at the hardwatre Kit.

Lab Work 1

20 Embedded Systems Lab

Complement is made by using “ Not “ …. Ex: x=0Xff, y=not x, y=0x00

1. Write a mikroBasic program that work as a flusher that load

“0x55” then load its complement to port B continuously.

2. Simulate the circuit using Proteus ISIS program.

3. Connect the circuit at the hardware kit.

Lab Work 2

21 Embedded Systems Lab

At mikroBasic code you must use delay. Delay is used in order to let the user se the

change … origional change is very fast and the user can’t notice it.

delay_ms(300) function : make a delay for 300 milliseconds.

… Good Luck …

Note

Include all your work during the lab for a complete report that

contains codes, simulation and hardware work with results.

Homework