Chapter 1 The Adventure Begins

1
Chapter 1 The Adventure Begins

• Creating the first project and saying Hello to
  the world

2
The Plan

• The first project with MPLAB IDE
• The project window
• The editor
• The output window
• A first statement
• A first complete program
• Controlling I/Os Ports and Pins
• Building the project
• Using the MPLAB SIM simulator
• The first debugging experience
• Hello World!

3
Preparation

• The following tools will be used in this lesson
• MPLAB IDE, Integrated Development Environment
  (v8.00 or later, free)
• MPLAB SIM, free software simulator (included in
  MPLAB installation)
• MPLAB C32, C compiler (free Student Edition)
• The following pieces of documentation will be
  used during this lesson
• PIC32MX Datasheet DS61143 (latest rev.)
• PIC32MX Family Reference Manual DS61120
  Section 12. I/O Ports
• Make sure they are available and/or installed and
  ready to use on your computer.
• You can download them from Microchip web site at
  http//www.microchip.com/mplab
• And http//www.microchip.com/c32

4
The New Project Set Up

• Launch MPLAB IDE
• Follow the New Project Set Up Checklist to
  create a new project using the Project Wizard

5
The New Project Setup Checklist

1. Select the PIC32MX360F512L device and click Next.
   
2. Select the PIC32 C-Compiler Tool Suite and click
   Next
3. Click the Browse button and create a new folder.
   Name the new folder Hello, and inside it create
   the project file Hello World, then click Next.
4. Click Next to proceed to the following dialog box
   since there is no need to copy any source files
   from any previous projects or directories.
5. Click on Finish to complete the project set up

6
The Project Window

• If not automatically visible, open the Project
  Window
• Select View-gt Project from the main menu

Note The project window can be made dockable
so that it will stick to one of the edges of the
screen (left)
7
The Output Window

• If not automatically visible, open the Output
  Window
• Select View-gt Output from the main menu

Note The output window can be made dockable so
that it will stick to one of the edges of the
screen (bottom)
8
The Editor Window

• Open a new editor window by selecting
• File-gtNew, or
• CTRLN keyboard shortcut, or
• by clicking on the corresponding button in MPLAB
  standard toolbar.

9
Creating a Source File

• Type the following three lines / Hello
  Embedded World! /
• Select File -gtSave As
• Save the file as Hello1.c.
• Now right click with your mouse on the editor
  window to bring up the editors context menu
• Select the Add To Project item.
• This will make the Hello1.c file the main source
  file in your project

10
Saving the Project

• Select Project -gtSave Project
• Save the project as Hello World.mcp

11
The First Statement include

• Add a first C statement
• include ltp32xxxx.hgt
• Which will actually include a file called
  p32mx360f512l.h whose content looks like
• ...
• extern volatile unsigned int WDTCON
  __attribute__((section("sfrs")))
• typedef union
• struct
• unsigned WDTCLR1
• unsigned WDTWEN1
• unsigned SWDTPS01
• unsigned SWDTPS11
• unsigned SWDTPS21
• unsigned SWDTPS31
• unsigned SWDTPS41
• unsigned 7
• unsigned FRZ1
• unsigned ON1

12
The main() function

• Add the following lines of code
• main()
• There can be only one main() function
• The curly brakets
• When is it executed
• What happens after it is executed

13
I/O PINS

• I/O pins can be configured as
• Digital Inputs
• Digital Ouputs (Push Pull)
• Digital Outputs (Open Drain)
• Analog Inputs
• Dedicated inputs or outputs for a number of
  peripherals

14
PORTA and PORTB

• Different PORTs group pins with different
  functions
• PORTB for example contains a number of pins that
  can be configured as analog inputs to the Analog
  to Digital Converter (ADC) .
• PORTA contains a number of pins that can be used
  for the JTAG interface, TRACE function, and the
  I2C interface
• Refer to the specific device datasheet for a
  detailed list of each PORT/pin capabilities

15
TRIS registers

• TRIS registers control the direction of each pin
  (Input/Output)
• TRISA, TRISB each port has a corresponding tris
  register
• Setting a bit to 1 configures a pin as Input
• Clearing a bit to 0 configure the corresponding
  pin as an output

16
The Watch Window

• Once a debugging tool (MPLAB SIM) is selected
• Open the Watch Window
• To inspect the content of a variable (symbol) or
  any of the special function registers (SFR)
• Select the desired output format(s)

17
Compiling and Linking

• A compiler transforms the C source code (.c) and
  all inlcuded (.h) files into a relocatable code
  object (.o)
• The linker takes all the relocatable code objects
  (.o) and libraries (.lib) and assembles them into
  an executable (.hex) file

18
Using the Simulator

• Follow the SetUp Checklist
• Learn the basic debugging options offered by the
  Simulator
• Reset
• Single Step (Over/In)
• Animation
• Running
• Halting

19
Debugging Hello World

• Set all pins of PORTA as outputs and then turn
  them on
• Notice how the JTAG port takes precedence unless
  disabled
• Now Try using PORTB
• Notice how by default the pins are configured as
  analog inputs and always read as 0 unleas
  re-configured

• include ltp32xxxx.hgt
• main()
• // configure all PORTB pins as output
• TRISB 0 // all PORTB as output
• AD1PCFG 0xffff // all PORTB as
  digital
• PORTB 0xff

20
Analog Pin Functions Multiplexing

• The Analog Pins control AD1PCFG

21
Summary

• In this lesson we learned
• How to create a new project
• How to create our first C source file
• How to build a project using the MPLAB C32
  compiler
• About PINs and PORTs
• How to configure and control simple digital
  output pins
• How to configure and use the MPLAB SIM simulator

22
Advanced Material
23
The Disassembly Window

• If you want to see what happens at the machine
  instruction level
• Open the disassembly window

24
The Memory Gauge

• If you want to see how much memory RAM and FLASH
  is being used by the project
• Open the Memory Gauge Window

25
Notes for the PIC MCU Experts

• The PIC32 PORTS are not necessarily 32-bit large.
  In fact most PORTS are 16-bit at the most.
• The PIC32 PORTS are designed to be compatible
  with the 8-bit and 16-bit PIC PORTS
• I/O PORT control in C is easy
• Use the LATx registers to control directly the
  output latches

26
Tips and Tricks

• Interfacing to 5V input and output signals is
  possible with some caution
• Digital Input pins are 5V tolerant
• Digital Output pins can be configured as Open
  Drain
• Use the ODCx registers to configure an output pin
  for Open Drain mode.
• Watch Out! Pins that are multiplexed with analog
  functions are NOT 5V tolerant!

27
Suggested Excercises

• If you have the Explorer16 board and an in
  circuit debugger
• Use the MPLAB REAL ICE Debugging or the MPLAB
  ICD2 Debugging checklists to help you prepare the
  project for debugging.
• Insert the instructions required to disable the
  JTAG port.
• Test the PortA example, connecting the Explorer16
  board and checking the visual output on LED0-7.
• If you have the PIC32 Starter Kit
• Use the PIC32 Starter Kit Debugging checklist to
  help you prepare the project for debugging.
• Modify the code to operate on PortD, but do NOT
  disable the JTAG port.
• Test the code by checking the visual output on
  LED0-2 on the PIC32 Starter Kit itself.
• In both cases you can
• Test the PortB example by connecting a voltmeter
  (or DMM) to pin RB0, if you can identify it on
  your board, and watching the needle move, between
  0 and 3.3V, as you single step through the code.

28
Recommended Readings

• Kernighan, B. Ritchie, D.
• The C Programming Language
• Prentice-Hall, Englewood Cliffs, NJ
• When you read or hear a programmer talk about the
  KR they mean this book!
• Also known as the white book, the C language
  has evolved quite a bit since the first edition
  was published in 1978!
• The second edition (1988) includes the more
  recent ANSI C standard definitions of the
  language
• The MPLAB C32 compiler adheres to the ISO/IEC
  98991990 (also known as C90) standard

29
Online Resources

• http//en.wikibooks.org/wiki/C_Programming
• This is a Wiki-book on C programming and as such
  it is a bit of a work in progress. Its
  convenient if you dont mind doing all your
  reading online.
• Hint look for the chapter called A taste of C
  to find the omnipresent Hello World! example.