AVR

Aug. 31, 2015, 9 p.m.

AVR, macro, Assembler

Macro - a set of commands and instructions that are grouped together into a single command to automate programming tasks, speed up frequently performed editing and formatting actions.

Macros can also be used to accelerate software development for microcontrollers on Assembler programming language. During compilation macros are replaced by a sequence of commands microcontroller. Such an approach to programming facilitates the perception of the program code, reduce the size of the source, as well as to bring the programming in Assembler in appearance to the programming language C.

Qt

Aug. 31, 2015, 10:39 a.m.

QMenu, QMenu example, QMenu Qt, Qt, контекстное меню, меню

To use the context menu in Qt is used QMenu class. When performing actions that should cause the menu handler is called, which creates the menu and binds handlers to act in this menu.

In this lesson, work with the shortcut menu will be shown in the example code from the tutorial on working with QDataWidgetMapper. In this lesson, the two files from the previous lesson will be modified, but the project will not work if you do not include it as in the previous lesson files that can not be edited.

Project structure for QMenu

Project structure remains the same as in the tutorial, which is based on the lesson. Changes in the code will be subjected to only two files:

  • mainwindow.h
  • mainwindow.cpp

Qt

Aug. 30, 2015, 10:33 a.m.

QShortcut, QShortcut example, Qt

Even in the official documentation on the topic QShortcut written not so much, so it's probably a note not to forget, not a full-fledged article. Just a few words about how to connect QShortcut entity that will be responsible for processing pressing a hotkey or keyboard shortcuts, such as Ctrl + D .

Project structure for QShortcut

The project structure is so trivial that I will not even bring it in this article. I shall confine myself to only those words that we will work with two files:

  • mainwindow.h
  • mainwindow.cpp

And even mainwindow.ui file will not touch this project. As it will be created by default, so it and leave.

Qt

Aug. 30, 2015, 3:40 a.m.

QSqlRelationalTableModel, QSqlTableModel, QSqlTableModel example, фильтр

Continuing to work with tables to Qt, we would like to spent the time, how to install the filter on the model of data representation in QSqlTableModel or QSqlRelationalTableModel . Therefore, the program code of the tutorial on QSqlTableModel was taken to describe the installation of the filter as a basis for the process.

The code was written in QtCreator 3.3.1 based on Qt 5.4.1.

Project structure

In this lesson, the project structure is similar to the project of the lesson QSqlTableModel.

mainwindow.ui

Add the additional object in the main window of the application, namely, to add the following elements:

  • dateEditFROM - start date;
  • dateEditTO - end date;
  • timeEditFROM - start time;
  • timeEditTO - end time;
  • pushButton - button, by pressing which the filter will be applied.

Qt

Aug. 28, 2015, 9:34 a.m.

Qt, QXmlStreamReader, QXmlStreamWriter, XML, xml example

Qt development tools include functionality for working with XML files, which allows you to create XML files and read them, which may be useful to create the automatic creation of XML markup software, configuration files, using XML, or for parsing XML-files .

To record in an XML file format used QXmlStreamWriter class, while the other is used QXmlStreamReader class to read an XML file.

The project structure for working with XML file

This project uses the minimum number of files:

  • XMLExample.pro - profile;
  • mainwindow.h - header file of the main application window;
  • mainwindow.cpp - source of window;
  • main.cpp - the main source file from which the application starts;
  • mainwindow.ui - form of the main application window;

AVR

Aug. 26, 2015, 9 p.m.

Attiny24, USI

USI - Universal Serial Interface (Universal Serial Interface) is actually a workpiece for hardware serial transmit and receive data. This interface is not a ready-made solution for some specific data transmission protocol, but provides a more convenient way to transfer data than in the case of full software solution.

The essence of this interface is that it offers a level of hardware to transmit and receive serial data and protocol operation logic is the responsibility of the software implementation.

Qt

Aug. 26, 2015, 9:15 a.m.

QPallete, QSplitter, QSplitter color, QSplitter example, Qt

Qualitative layout always increases application usability, and this is true for all kinds of applications, from desktop to mobile. One such interface elements, which can improve usability is QSplitter class, which is an object-type layout with a movable divider that separates the two areas in the application interface.

Project Structure for QSplitter

Project Structure for QSplitter

Project structure completely unremarkable and a little interesting, since the main actions will be carried out in the designer, and QSplitter in mainwindow.cpp setting will produce a minimum.

AVR

Aug. 24, 2015, 9 p.m.

Attiny, MUL

MUL - multiplication instruction in microcontrollers, is present, for example, microcontrollers Atmega. But not all AVR microcontrollers there is hardware support multiplication of functions. For example, in microcontrollers Attiny MUL team simply does not exist, so the solution to this problem lies with the program code.

The main point to be taken into account in the implementation of the multiplication function is that to save the multiplication result will need two registers. In one of the registers will be kept low byte of the result, and in the second case bude saved significant byte result.

AVR

Aug. 22, 2015, 9 p.m.

BCD, Atmega

Decimal numbers machine language may be represented in the form of eight-bit sequences of ones and zeros, that is bytes. However, there are two types of presentation formats decimal numbers. It is packed format (BCD), and unpacked.

Uncompressed format

In this format, one digit of a decimal number is placed in one byte. Namely LSnibble bytes, whereas the most significant nibble (referred to as a zone) is filled units. For example, the number 157 would be as follows.

AVR

Aug. 21, 2015, 9:30 p.m.

TWI, Atmega

I remembered a little hardcore in Hardwar with TWI interface, which takes a few years ago. Who would not say, and Assembler perfectly cleanses the brain and develops an understanding of the algorithms. The most important thing I learned while working with AVR microcontrollers on Assembler, is the fact that all the operations, all directives, all functions must be written in a clear sequence. After all, if the write data in the register is not in the sequence, then your controller firmware does not work. And when writing code in high-level languages, sometimes you can see a complete indifference to the sequence of calling functions and methods, though often in the instructions to the libraries can be read, in what order you need to initialize a particular functionality, to get everything working. But who would read them carefully? Well, if you dear reader to read this paragraph instead skopipastit immediately imagine a software library of code that is shown below.

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Last comments
March 27, 2020, 2:40 p.m.
Evgenij Legotskoj

Добрый день. В конце пятой статьи скачать можете.
March 27, 2020, 2:28 p.m.
mkdir _

Здравствуйте, а можно, пожалуйста, ссылку на целые исходники, если есть?
March 27, 2020, 4:36 a.m.
Evgenij Legotskoj

Скорее всего также, как и для установки всех остальных переменых в CMake, через использование set
March 27, 2020, 2:47 a.m.
Andrej Jankovich

Ошибка с ярлыками в Windows исправлена в версиии 1.4.0.4
March 26, 2020, 1:37 p.m.
Andrej Jankovich

но появятся ярлыки, сейчас поправим
Now discuss on the forum
March 30, 2020, 4:16 a.m.
Evgenij Legotskoj

Попробуйте запустить через плейлист, а не через setMedia. Пример есть в этой статье
March 30, 2020, 3:25 a.m.
Evgenij Legotskoj

Добрый день. Почитайте документацию, в исходниках этой библиотеки есть исходнные классы логгеров. Вам наверняка достаточно только правильно вызвать пару функций, чтобы задать имя файла…
March 30, 2020, 3:17 a.m.
Evgenij Legotskoj

Нет, не нужно ничего умножать, если у вас включена поддержа High DPI в приложении а QML, то достаточно держать в памяти, что все значения задаются в DPI, и просто задаёте значения равные DPI сра…
March 27, 2020, 10 a.m.
Mihailll

Оказывается нужно сделать столбец уникальным ALTER TABLE public.drivers ADD UNIQUE (agregator1_id); Потом так работает INSERT INTO drivers( name_driver, surname, middle_name, agr…
s
March 27, 2020, 8:25 a.m.
shuric

Спасибо за ответы. Скорее всего оставлю на неопределенное время под macOS. Хоть будет полезно другим начинающим разработчикам.
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