Developers Club geek daily blog

OpenOCD, GDB and (strongly) remote debugging

1 year, 6 months ago
It is given: there is a device, with ARM926E-JS (Cypress FX3) onboard. The device is on other continent. The device is connected (JTAG+USB+COM) to Linux to a computer. On a computer there is SSH access (more than nothing, only SSH port).

Problem: The device needs to be debugged and written under it a code. And to do it, it is desirable, conveniently.

Solution with use of OpenOCD, GDB and Qt Creator, and also the description of a way to it, under a cat.

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Editing an image of Raspberry Pi by means of qemu-user-static (Ubuntu 14.04)

1 year, 6 months ago
image

Sometimes editing standard boot images, and also configuring of systems with the subsequent replication on a large number of payments of Raspberry Pi is necessary. For a solution of similar tasks it is convenient to use packets of qemu-user-static and binfmt-support.

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Performance measurement of functions in JavaScript

1 year, 6 months ago


Performance always played a key role in the software. And in web applications its value is even higher as users can easily go to competitors if the website made by you works slowly. Any professional web developer has to remember it. Today it is still possible to apply successfully the mass of old acceptances of optimization of performance, like minimization of amount of requests, use of CDN and not use to rendering of the blocking code. But the more developers apply JavaScript, the problem of optimization of its code becomes more important.

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Investigation of a setup error of the Visual Studio of 2015

1 year, 7 months ago
We decided to transfer somehow the project to the Visual Studio 2015 — there to so many fascinatingfeatures ! Yesterday here only solved, and already this morning I started its installer. The sky was cloudless, nothing portended trouble. Well, really, can go not so? How many already these Visual Studios it is rearranged — not to consider (I, am remembered, 6.0 more once put). Who could think that this most trivial task can develop into very unexpected running on a rake long almost in the whole working day.

Having crackled a little hard drive, the beautiful installer showed me absolutely ugly error message. Here it:


Hm. It was not put means, Team Explorer and couple more of minor packets. Well ok. We close, we reinstall. Does not help. We delete studio, we reboot, we set — the same error. We climb in Google with a question of a setup error of the Visual Studio of 2015 at a stage of installation of the Team Explorer component and we understand that the problem is mass — tens of links with the same description:
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17

Specialists of the first line of technical support of Microsoft whose councils are reduced to "answer all these questions disconnect an antivirus", "check a cheksuma of an image with studio", "check a disk for errors". Nothing from this, of course, helps what they and are told about then they vanish and do not answer any more. Very friendly user support, you will tell nothing.

Well, it is time to include the head, to take tools in hand and to understand. Went.

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We write the software for generation of data of a musical card. Part one: we sort the MIDI file

1 year, 7 months ago

Introduction


In the articles about transition to the Russian K1986BE92QI microcontroller I time told about generation of a sound means of the microcontroller. Then before me the task only to reproduce data melted. For creation of these data obtained from MIDI files very exotic methods, for example, as in this article were used. Yes, similar methods have the right to life if it is required to obtain data for reproduction few times in life. But as I rather often face tasks when on the controller it is necessary to receive rather difficult sound, or a sound — only an additional option, a task to transform MIDI files by such exotic methods, to become very nontrivial. In this small series of articles I set for myself the task to create (and for one and to tell in detail about creation process) the universal program for the MIDI conversion of files to a format, acceptable for the microcontroller, and also generating all these initialization, necessary for the microcontroller.



Implementation of the main functionality of the program will become a result of this article: creation of arrays a note duration, created from the MIDI file. Who became interested — I ask under kat.

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Writing of the elementary program under Linux in machine codes

1 year, 7 months ago
All hi. I wanted to touch this subject long ago and to write something similar, but hands did not reach in any way. Today I decided, and we will sort structure of the ELF file (the performed file on * nix-like systems), and we will write the simple program under x86 Linux in machine codes which will display the message. But here not everything is so unambiguous, believe me.

I wanted to begin with the end. Namely from what will be done by our program. Our program — no other than a heap of machine code which, afterwards, will be performed by system. As the deputy of numeration system of Hex I will use "Wct" because it is much more convenient because there is online the compiler and an opportunity to insert lines on the run and to use decimal numbers. At us it will display one line of the text.

image

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iOs Debug Master

1 year, 7 months ago
Once I almost completely refused a mouse for navigation on Xcode and is quite glad to it. The following step is a failure from visual control facilities a debugger. What for? — we Increase opportunities, we reduce time of a debag, we spend less calories for movement of a tyazhelenky ruchishka (calories are necessary to us, that to work the head) and by that we provoke less tunnel syndrome.


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We pass from STM32 to the Russian K1986BE92QI microcontroller. Practical application: We poll keys, we manage the LED brightness (we generate tension on an output) by means of PWM (PWM+TIM+PORT)

1 year, 7 months ago

Introduction.

In two previous articles we generated a clock signal of the frequency necessary to us by means of PWM, receiving on a LED equal intervals of a luminescence and its absence. This task takes place to be in practice (in one of the subsequent articles we will precisely face it). But most often PWM is used for other designated purpose. One of the most widespread — management of brightness of LEDs or the rotational speed of motors. Also by means of PWM it is possible to generate a sound (about what there will be following article). And in this article I would like to tell how on our controller it is possible to implement management of LED brightness.

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We pass from STM32 to the Russian K1986BE92QI microcontroller. Practical application: We poll keys, we generate PWM. Comparison of a code on CMSIS and SPL (PWM+TIM+PORT). Part second

1 year, 7 months ago

Introduction.

In the previous article we repeated the general structure of the timer and in details considered manual method of adjusting PWM of the channel with use of CMSIS. But much do not like "to dig in registers" and they prefer essentially other abstraction layer allowing as it seems to them, to simplify a task. I will try to show in this article to you all pluses and minuses of this approach.

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Использование VTune Amplifier 2016 для анализа приложения HelloOpenCL для GPU

1 year, 7 months ago


VTune Amplifier 2016 можно использовать для анализа программ OpenCL. В этой статье вы узнаете, как использовать это решение, а также как создать простую программу OpenCL под названием HelloOpenCL с помощью Microsoft Visual Studio и Intel OpenCL code builder.

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