Program Flow In Embedded C

Program Flow and control is a control method of your program. For example Loop constructions control repeated execution of repeated program segments where control is taken by control parameter. In this article we will go through if/else switch/case statements and loop sentences like while, do while, for. While statement As I mentioned three looping sentences available in C language one of them is While sentence. Lets take an example: #include <stdio.h> int main(void) { int guess, i; i=1; guess=5; while (guess!=i) { i=guess; guess=(i+(10000/i))/2; } printf(“Square root of 10000 is %d\n”, guess); return 0; } While(guess!=i) invokes looping operation. This causes statement to be executed repeatedly at the beginning the condition guess!=i is checked. As long the argument is TRUE the while sentence will be continued continuously. When guess becomes equal to i while statement will be skipped. I am not going to deep in to it as there are…

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Why C instead ASM

ASM is a specific language also referred as low level programming language. It is a mnemonics to a machine codes. It usually takes long time to develop embedded programs in ASM language. Today even modern 8 bit microcontrollers are powerful and complex as they were long time ago. The program memory of tiny chips are reaching megabytes, they pack lots of peripherals and interfaces. Hardware code is becoming more complex, functionality grows up. This is one of the main reasons of using higher level programming languages like C. By using C language you do not have to go into details how processor works at hardware level. You don’t have to think about hardware logic how bytes are shifted between registers. It is better to leave t Another advantage of C language against ASM is portability. If you work with embedded system architecture and decide to move to other, and your…

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AVR GCC Structures

Basically Structures are nothing more than collection of variables so called members. Structures allows to reference all members by single name. Variables within a structure doesn’t have to be the same type. General structure declaration: struct structure_tag_name{ type member1; type member2; … type memberX }; or struct structure_tag_name{ type member1; type member2; … type memberX } structure_variable_name; in second example we declared the variable name. Otherwise variables can be declared this way: struct structure_tag_name var1, var2,var3[3]; Members of structure can be accessed by using member operator (.). The member operator connects the member name to the structure. Lets take an example: struct position{ int x; int y; }robot; we can set robot position by using following sentence: robot.x=10; robot.y=15; or simply robot={10,15}; Structures can be nested: struct status{ int power; struct position coordinates; } robotstatus; to access robot x coordinate we have to write: x=robotstatus.coordinates.x; Actions can be taken with…

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Accessing AVR microcontroller ports with AVR GCC

All AVR ports have Read-modify-write functionality when used for general I/O functionality. Direction of each separate port pin can be changed. Each pin buffer has symmetric capability with ability to drive and sink source. Pin driver is strong enough to drive LED directly, but it is not recommended to drive even small loads without using proper driver circuit such as transistors. All port pins have internal selectable pull-up resistors. And finally all pins have protection diodes to both VCC and GND rails. Each port of AVR consists of three registers DDRx, PORTx and PINx (where x means port letter). DDRx register selects direction of port pins. If logic one is written to DDRx then port is configured to be as output. Zero means that port is configured as input. If DDRx is written zero and PORTx is written logic “1” then port is configured as input with internal pull-up resistor.…

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Why Using Ruby on Rails

Nowadays many big and small companies prefer using Ruby on Rails when creating applications that are to be delivered on the web. It is not surprising, as Ruby on Rails offers lots of advantages over other web development frameworks. Lets have a closer look at the benefits of Ruby on Rails or Ruby, as it is usually called. The main advantage of this framework is that it makes the life of a web developer easier, by allowing writing less code, which is achievable due to a leaner code base. Ruby on Rails is very easy to use. Beside, it gives speed and flexibility that no other scripting language or framework can give. Creating websites with Ruby on Rails is a lot faster and easier than with other web developing solutions. Generally, to develop and launch a website, developer needs about twelve weeks. While using Ruby on Rails, a web developers…

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Agile Web Development with Ruby on Rails

What is Ruby on Rails? Ruby on Rails (known also as RoR or simply Rails) is an object-oriented, multi-level, full-stack framework running via a programming language called Ruby. Many web developers choose to work in Ruby on Rails due to its numerous advantages. Why do developers love RoR? The best known advantage of Ruby on Rails web development is the speed. A variety of handy instruments and the support offered by Ruby on Rails community increase the speed of development by about 30-40%. With Ruby on Rails, you get excellent built-in testing, caching, localization, validation and deployment tools. And that’s not it. You also get an opportunity to customize routing and titles of the website sections, so that your projects always have simple and beautiful URLs. Database migration process is perfect in Rails. The database structure always stays in the repository, and every change in structure gets instantly documented.

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Reading serial data from chipKIT UNO32 using Python3 and pyserial

installing python3 - path variable

Python is a great programming (scripting) language that is supported on all platforms. Embedded enthusiasts love it because of variety of modules that allows connecting things to internet and other crazy stuff by writing only few lines of code. Today my interest was to read serial data with using Python 3.3 and pyserial module. Python 3.3 is still new and there is a majority of modules that needs to be ported from Python 2 to Python 3, but I hope soon they will here. Serial module seems to be working fine in Windows 7 x64 and decided to share my experience. First of all download and install Python 3 (current release is Python 3.3) Just be sure to include “Add python.exe to Path” so you could run Python anywhere in you computer. We wont go in to details on how to setup this tool. It is pretty robust. After setup…

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