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For many people who learn embedded linux, there are always many problems in the process of learning. Relatively speaking, embedded linux is also relatively difficult in embedded learning. How can we overcome this difficulty? then we need to start from the root. One of the most important points in learning embedded linux is the process of embedded linux development. Look at embedded development Daniel how to understand embedded linux development, here are some summary of the specific development process, of course, in addition to the process, there will certainly be a lot of problems, here will also answer for you.

The process of embedded development is actually very simple, but there are a lot of small things you need to pay attention to. This is also the experience of so many years. Let's first look at the specific process:

First, to establish a development environment, you must first be able to install and configure the embedded linux development environment, which is the basic

Of course, the operating system is LInux, or install the virtual machine under the win system, download the corresponding GCC cross-compiler through the network to install, or install the cross-compiler provided by the product manufacturer.

This step is equivalent to installing an IDE development environment, such as MDK,IAR, under the win system. At this point, I often have some problems because of this, just because the configuration is not well matched, the following steps can not be carried out, report an error, and keep in mind that you need to be careful here.

Second, configure the development host

Mainly configure minicom, that is, serial port assistant, minicom software is used as a monitor and keyboard input tool to debug the information output of embedded development board, is a very convenient tool, when we develop other embedded programs, in fact, we often use serial port debugging, so the final principles are the same.

1. Embedded linux development process

Configure the network, mainly to configure the NFS network file system, this is mainly used to download programs, of course, you can not configure, there are many other ways.

Third, set up the bootloader installed in the program.

The commonly used bootloader is mainly u-boot, vivi and so on, and it seems that the mainstream is u-boot, which is transplanted and modified according to its own specific chip. Some chips do not have built-in boot loaders, which requires the preparation of less Flash programs on the development board, of course, you can also use less Flash chip procedures under windows through the JTAG parallel port and simulator, and there are also open source J-Flash procedures under linux. When you do it yourself, you can reserve multiple ways, which is useful.

To put it simply, in fact, it is necessary to make a u-boot of your own board, complete initialization, kernel boot, download, burn, and so on. In fact, at this point, it will also be a difficulty, there are many things need to be mastered here, this process of burning and writing, kernel boot, there are free downloads of Windows through the JTAG parallel port simple simulator burning ARM peripheral Flash chip burning program, there are also open source code under Linux J-Flash program. If you can't burn your own development board, you need to modify the source code according to your own specific circuit. This is the first step in the normal operation of the system. Of course, it is easier to burn Flash if you buy a manufacturer's simulator, which can greatly improve the development speed for people who need to develop their own products quickly, but the core technology is impossible to understand.

Linux embedded development process, listen to what the awesome people have to say

Then there is the embedded Linux operating system to transplant www.hqyj.com. If you want embedded linux engineers to earn more and earn 13000 yuan a month, you still need to master the following knowledge.

1. Embedded linux development process

If there is a Linux specifically for your CPU, such as uCLinux, ARM-Linux, PPC-Linux, etc., if not, you should try to migrate your own linux, and then add your own specific hardware driver to debug and modify it. For CPU with MMU, you can use module mode to debug the driver, while systems like uCLinux need to be compiled into the kernel, integrated with the kernel, and then debugged. The best thing is to download the Linux operating system that has been transplanted by others, which will be efficient.

2. Then comes the root file system.

As mentioned in the previous article, Linux doesn't work without a root file system, and you need a root file system. So you need to download and use busybox software to make the root file system.

Then add other programs according to your own application needs, and the default startup script generally does not meet the needs of the application (because all embedded developers are customized freely), so it is necessary to modify the startup script in the root file system. Its storage location is in the / etc directory, including / etc/init.d/rc.S, / etc/profile, / etc/.profile, etc. Automatically mount the file system configuration file / etc/fstab, in fact, is to customize the program to boot, the specific situation will vary with the system, the root file system in the embedded system is generally set to read-only, you need to use mkcramfs, genromfs and other tools to generate fewer image files. Remember to watch this step and don't make mistakes in order to save time.

After getting the above done, the next step is to set up the Flash disk partition of the application.

Jffs2 or YAFF file systems are generally used, which requires providing drivers for these file systems in the kernel. Some systems use NOR FLASH, some systems use NAND FLASH, and some systems use both flash, depending on the circumstances.

3. Develop applications

Applications can be placed in the root file system, yaffs, jffs2 file system, some applications do not use the root file system, and directly design the application and the kernel together, which is similar to uCOS-II.

In fact, the above steps are for this step, and here you should note that he can be presented in three ways:

(1) directly talk about the design of the application and the kernel, similar to the way of uCOS-II

(2) developing applications based on GUI such as qt

(3) there is no screen, only simple man-machine interface, such as serial port, button, digital tube, which can also realize the development of complex functions.

Now it's time to load the burning kernel, root file system, and applications (in fact, it's almost over).

No matter how to load the module, all these development, process materials, are to be burned into the flash, and then what the application needs, you can load the corresponding functional program.

4. Release the product

To develop a medium-to-high-end controller device with complex functions and even complex screen interactions, such as mobile phones (Android is the son of linux and OS is the cousin of linux), cash machines and server trading systems, then linux is very suitable.

Develop a small controller device, if the function is not too complex, you can use a slightly advanced CPU, bare metal or ucos to develop, but also very convenient, but also can do a lot of customized versions of industrial small controllers.

According to my many years of experience summary is here, and embedded linux development process is these, with the above steps, to master embedded linux learning is very simple, these methods you have get to, are actual combat experience.

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