Using the EE 109 Tools. Allan Weber Mark Redekopp

Transcription

1 1 Using the EE 109 Tools Allan Weber Mark Redekopp

2 2 Note and Disclaimer Please follow the instructions at to setup new labs/projects for your Arduino Some of this material is just background info that is just for reference the stuff we'll use a lot will be repeated as we do it more and more.

3 3 Building a Program The programming/debugging loop: Edit [emacs, TextWrangler, Notepad++] Compile/Link [make, avr-gcc] Download and execute [make flash, avrdude] Observe [ you! ] Repeat [ you! ] Programs can be edited in any plain text editor Available on the VHE 205 Macs: Emacs (command line program) Vi/Vim (command line program) TextWrangler (Mac GUI app) Don t use a word processor (Microsoft Word or Apple TextEdit etc.) How to start a fight: Tell another programmer that your favorite text editor is better than theirs.

4 4 Editing the Program [Mac/Linux] To run command line editors on the Mac, start the Terminal application from the dock at bottom of the screen Emacs and Vi require some knowledge of a few Unix-type commands in order to be useful (cd, ls, rm, more, etc.) Run the editors by just typing the editor name and the name of the file. emacs myfile.c vi myprog.c

5 5 Emacs Quick Reference [Mac/Linux] Emacs uses the keyboard for all editing commands. Easiest way to learn is via the built-in tutorial. Type the command emacs and then once in the editor, enter the command ESC X helpwith-tutorial Read along and follow the instructions

6 6 Emacs Quick Reference [Mac/Linux] Open (Ctrl-x, Ctrl-f) Then type in the name of the file to open or create if it doesn't exist Save (Ctrl-x, Ctrl-s) Exit (Ctrl-x, Ctrl-c) Cancel Command (Ctrl-g) Cut a whole line of text (Ctrl-k) Cut a segment: (Ctrl-space) at start, (Ctrl-w) at end Paste (Ctrl-y) Search (Ctrl-s) then type the word and hit enter Hitting Ctrl-s again will go to the next occurrence

7 7 Editing the Program [Mac] The TextWrangler text editor can be started by dragging and dropping the program file onto the icon in the dock.

8 8 Editing the Program [Windows] The Notepad++ text editor can be started by First selecting the file (left-click) in Explorer Then right-click the selected file and choose 'Edit with Notepad++'

9 COMPILATION UNITS 9

10 10 Compilation Units Often rather than putting all our code/functions in one file it is easier to maintain and re-use code if we break them into multiple files We want functions defined in one file to be able to be called in another But the compiler only compiles one file at a time how does it know if the functions exist elsewhere? #include <avr/io.h> void flash(int delay) { PORTB = (1 << PB5); _delay_ms(delay); PORTB &= ~(1 << PB5); _delay_ms(delay); } int main() { flash(500); // do something else flash(1000); return 0; } flash.c flash1_test.c

11 11 Compilation Units We must prototype any function we want to use that is in another file Rather than make us type in the prototypes for each new program we write that needs that function, put prototypes in a header file that can be reused (included) for any new program void flash(int delay); int main() { flash(500); // do something else flash(1000); return 0; } flash1_test.c void flash(int delay); flash.h #include <avr/io.h> void flash(int delay) { PORTB = (1 << PB5); _delay_ms(delay); PORTB &= ~(1 << PB5); _delay_ms(delay); } flash.c #include "flash.h int main() { flash(500); // do something else flash(1000); return 0; } flash1_test.c #include "flash.h int main() { int i=1000; while(i >= 200){ flash(i); } return 0; } flash2_test.c

12 12 Compiling to Object Code Two issues: We may not want to distribute our source code files With a large program, we don t want to re-compile all the files if the code only changed in one Solution Compiling to object code, creates the machine code/assembly code for just a single file BUT DOESN T try to link any function calls to other files nor does it try to create an executable Use: gcc c filename.c void flash(int delay) { PORTB = (1 << PB5); _delay_ms(delay); PORTB &= ~(1 << PB5); _delay_ms(delay); } gcc c flash.c flash.c flash.o

13 13 Linking After we compile to object code we eventually need to link all the files together and their function calls Without the c, gcc will always try to link You can give gcc source files (.c files) or object (.o files) flash.c (Plain source) gcc -g Wall c flash.c flash.o (Machine / object code) gcc -g Wall o flash1_test flash.o flash1_test (Executable) flash1_test.c (Plain source) gcc -g Wall c flash1_test.c flash1_test.o (Machine / object code) flash1_test.o Note: gcc -g Wall o flash1_test flash.c flash1_test.c Would also work and be fine and thus not require you to compile to object code in a separate step

14 14 gcc/g++ Options Most basic usage gcc c_filenames Creates an executable a.out Options -o => Specifies output executable name (other than default a.out) -g => Include info needed by debuggers like gdb, kdbg, etc. -Wall => show all warnings -c => compile but don't link (i.e. create an object file) -Ipath => add path into #include search directory -Lpath => add path into library search directory -Dmacro => #define macro -llibname => link in the code in library, libname -On => n=[0..6] => Optimization level 0-6

15 COMPILING THE PROGRAM 15

16 XKCD # Courtesy of Randall

17 17 'make' and Makefiles We really use the 'avr-gcc' compiler (just like you use g++ for CS 103) But to compile for the Arduino requires many complex settings/options Also, a single program can be made of many source files and library code files 'make' is a utility program on most Linux/Unix machines which processes commands in a provided Makefile Helps automate compilation process Essentially can use Makefiles as scripts of commands to be run Let make fill in all the complex compilation options Helps provide 'smart' compilation Compiles only files or those that depend on files that have changed since last compilation Reduces wait time for compilation process especially for large programs

18 18 Analogy: Evaluating Expressions Take the equation: x = 5*y + (8*z + 3) Evaluate for y=9, z=7 We evaluate term by term & add What if only y changed and we needed to find the new value of x? What would you reevaluate What if only z changed, what operations would be needed to find the new value of x

19 19 Smart Compilation Only compile code that has changed and any files that DEPEND on that code flash.c (Plain source) [ CHANGED ] gcc -g Wall c flash.c flash.o (Machine / object code) flash1_test.c (Plain source) flash.h gcc -g Wall c flash1_test.c flash1_test.o (Machine / object code) gcc -g Wall o flash flash.o flash1_test.c flash1_test (Executable)

20 20 Compiling the Program A 'Makefile' tells 'make' what files the program is composed of how they depend on each other how to compile each file (convert.c to.o or.o to an executable) 'make' looks at the modification dates on files to determine what needs to be compiled, and only compiles what it has to. Program main.o input.o output.o library1.a main.c input.c output.c sub1.o sub2.o sub3.o proj_defs.h sub1.c sub2.c sub3.c

21 21 Compiling the Program The make program uses the text file Makefile for information on the dependencies (i.e. The contents of 'Makefile' is the script that tells 'make' what to do) Sample Makefile

22 22 The "Makefile" for the Lab 2 program. Most of it is boilerplate and can be ignored. Only requires minor changes to stuff at the top Compiling the Program Change the objects line to contain all the file prefixes your project requires with a.o extension Ex: OBJECTS=flash.o flast1_test.o

23 23 Compiling the Program Edit the program lab2.c file is now newer than the lab2.o file Run make Compiles lab2.c Links to create main.elf Everything up-to-date Make doesn t do anything

24 24 Downloading the Program The make program is also used to download the binary data to the Arduino. Connect the USB cable to the Arduino. make flash to start the download.

25 25 Helpful reference but not needed STOP HERE OTHER NOTES

26 CONDITIONAL COMPILATION 26

27 27 Multiple Inclusion Often separate files may #include's of the same header file This may cause compiling errors when a duplicate declaration is encountered See example Would like a way to include only once and if another attempt to include is encountered, ignore it class string{... }; #include "string.h" class Widget{ public: string s; }; #include "string.h" #include "widget.h" int main() { } string.h widget.h main.cpp class string { // inc. from string.h }; class string{ // inc. from widget.h }; class Widget{... } int main() { } main.cpp after preprocessing

28 28 Conditional Compiler Directives Compiler directives start with '#' #define XXX Sets a flag named XXX in the compiler #ifdef, #ifndef XXX #endif Continue compiling code below until #endif, if XXX is (is not) defined Encapsulate header declarations inside a #ifndef XX #define XX #endif #ifndef STRING_H #define STRING_H class string{... }; #endif #include "string.h" class Widget{ public: string s; }; #include "string.h" #include "string.h" String.h Character.h main.cpp class string{ // inc. from string.h }; class Widget{ // inc. from widget.h... main.cpp after preprocessing

29 29 Conditional Compilation Often used to compile additional DEBUG code Place code that is only needed for debugging and that you would not want to execute in a release version Place code in a #ifdef XX...#endif bracket Compiler will only compile if a #define XX is found Can specify #define in: source code At compiler command line with (-Dxx) flag g++ -o stuff DDEGUG stuff.cpp int main() { int x, sum=0, data[10];... for(int i=0; i < 10; i++){ sum += data[i]; #ifdef DEBUG cout << "Current sum is "; cout << sum << endl; #endif } cout << "Total sum is "; cout << sum << endl; stuff.cpp $ g++ -o stuff DDEBUG stuff.cpp

30 MAKEFILES 30

31 31 make utility Looks for commands in a file called Makefile or whatever is given as the f option on the command line Makefile is a text file with rules (a.k.a targets), dependencies and actions along with macros if desired rule: dependencies [TAB] action1 [TAB] action2 Rules => outputs; Dependencies => Inputs; Actions => commands to build the output from inputs To run the Makefile, we use the make command from the command prompt: make [-f filename] [specific_rule] If no target specified at command line, 'all' target is made:

32 32 Environment variables From the Linux shell (terminal) we can set "variables" that contain values that can be accessed by other programs that provide system and other info PATH LD_LIBRARY_PATH Set with export command export VARIABLE=VALUE Access value with $VARIABLE in shell Access value with $(VARIABLE) in Makefile We defined CXXFLAGS in most of your.profile or.bashrc (startup script) CXXFLAGS = -g -Wall

33 33 Defining macros/variables Makefile MACRO_NAME = MACRO_DEF SRCS = test.cpp prog1.cpp FLAGS = $(CXXFLAGS) # if CXXFLAGS defined by shell Using macros $(MACRO_NAME) $(SRCS) Built-in Macros $< = dependency name / name of the related file that caused the action $@ name of the file to be made / target name Macro Modification OBJS = ${SRCS:.cpp=.o} Substitute.o for.cpp wherever it occurs in the expansion of SRCS

34 34 Example Example wget tar xvf makeex.tar cd makeex test1: foo.cpp bar.cpp test1.cpp test2: bar.cpp list.cpp Two Makefile Makefile.basic Just hard code dependencies I might suggest you go this route for your assignments easier for now Makefile.inter Intermediate: uses some substitutions to be more general proj common src include build src foo.cpp bar.cpp test1.cpp test2.cpp foo.h list.h bar.h Put your.o & exec here list.cpp