AVR-GCC ABC [2]

After release of AVRStudio4 there is ability to integrate AVR-GCC compiler in it. As you know AVR studio has only assembler compiler- debugger. Integration of AVR-GCC is done by plugin. Plugin detects AVR-GCC by it self, you don’t have to bother. What do we get from it? Of course – full set of good tools comparable to commercial. Convenient user interface, automatic makefile generation, visual debugging by watching processors register, or even you can flash the chip. We can say that abilities are: 1. Compilation, setting parameters, automatic AVR-GCC detection; 2. Graphical User Interface – convenient project setting; 3. Tree like project view; 4. Project can be complied with predefined configurations; 5. Convenient error handling; 6. Ability to use external makefiles; 7. Map and List file generation; 8. Plugin inspect connections among source files(c and h files who are not part of project); 9. User can work with c or…

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AVR-GCC ABC [1]

This time I decided to lay down some information on using AVR-GCC compiler. I am not going to rewrite what’s in documentation is already written, but just write down some issues, what can help you start using this amazing tool. Introduction Probably the most AVR programmers had a question in their mind what compiler to use for their designs. The choice is really big. You can use commercial ones like IAR, CodeVision, ImageCraft. These compilers come with convenient GUI’s, code generators. But you have to buy license to use them. So if you are going to make low budget project, the best choice is to use open source compiler GCC . This is the most successful open source compiler in the world. For AVR platform it is called AVR-GCC. The compiler itself has no graphical interface everything can be done in MSDOS command line or in Linux command line. To…

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C language Operators and expressions

The main thing what microcontrollers does is operates with data. There are four main operations that microcontrollers does: adds, abstracts, multiplies and divides (+,-,*,/). division can be split in division “/” and modulus operation “%”. For instance i1/i2 is integer division. Other part of operators is Relation operators. They are used for boolean conditions and expressions. Expressions with these operators return true or false values. Zero is taken as false and non zero value as true. Operators may be as follows: <, <=, > >=, ==, !=. The priority of the first four operators is higher than that of the later two operators. These operators are used in relational expressions such as: 7 > 12 // false 20.1 < 20.2 // true ‘b’ < ‘c’ // true “abb” < “abc” // true Note that the equality operator is == and not =. ‘=’ is an assignment operator. If you want…

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Constants in C language

Constant value is understandable as non changeable value like PI=3.141592… value in math. Usually you use constants in your programs, but don’t realize that they are constants. For instance: x=x+3; The number 3 is a constant which will be compiled directly in addition operation. Constants can be character or string. Like in function printf(“Hello World\n”); “Hello World” is a string constant which is placed in program memory and will never changes. It is usually recommended to declare constants by using identifier with reserved word const: const int No=44; By identifying the variable as constant will cause compiler to store this variable in program memory rather than in RAM, thus saving space in RAM. If special functions used, then constants can be also stored in EEPROM memory. Few words for the numeric constants. Numeric constants can be declared in many ways indicating their base. Decimal integer constants (base 10) consist of…

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The very basics of C

C language is function based programming language. C program itself is a function. Usually parameters to C function are passed as arguments. Function consists of a name followed by the parentheses enclosing arguments or an empty pair of parentheses if there are not arguments required. If there are several arguments, they are separated by commas. The mandatory part in C program is main function. This function must be included in every program because this is a first function which is run after execution of program. Lets take an example: #include <stdio.h> int main(void) { printf(“Hello world!\n”); return 0; } This is a very basic C program, but it contains all necessary elements of it. Lets examine a little bit what we have written here…

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Microcontroller C programming

There is no doubt that everyone faces C language when programming microcontrollers. This is most popular language among hardware programmers. There are plenty books about this language – you just have to open and read. This article is not about language basics, but there is effectiveness of c language in embedded systems touched. Quite often you can find good examples of effective algorithms: faster code performance and code size as well. In order to write good optimal algorithm you have to know structure of compiler. Of course we are not going to analyze compilers, but we can look through few rules and tricks and achieve optimal algorithm. Begining What to do when limit of program size is overrun or there is not enough speed in some cases. Of course you will say, that these parts it is best to write in assembler, but is this a solution? Maybe there is…

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GNUARM for ARM microcontrollers

In this article you’ll find some information about how to configure GNUARM toolset for compiling ARM7 microcontrollers. GNUARM is the open source toolset for ARM7 MCUs. It has GCC compiller and debugger. Our purpose now is to set up tools in Windows environment and compile one project. First of all download compiled toolset from http://www.gnuarm.com: Select the newest [GCC-4.0 toolchain] located bellow Cygwin. After it is downloaded, start the installation: 1. Start window 2. Accept license agreement. 3. Select folder where do you want GNUARM to be installed: 4. Select the components. You can select all of them. 5. Chose Start menu folder name – just leave as it is. 6. Select desktop shortcut to be placed. I higly recoment to check Cygwin DLL, because despite I had cygwin installed, but I had to copy DLLs to copy manually. If this option ischecked, DLL files will be copied without bothering…

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