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

• Select the PIC32MX360F512L device and click Next.
  
• Select the PIC32 C-Compiler Tool Suite and click
  Next
• 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.
• 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.
• 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.