Uboot common command summary analysis

U-boot has evolved to the present, his command line mode is very close to the shell under Linux, and the command completion and command history of the "Tab" key is supported in the command line mode mode of my compiled U-boot-2009.11. Recording function. And if the first few characters of the command you entered are not duplicated with other commands, then you only need to type these characters. For example, if I want to see the version number of this U-boot, the command is "version", but No other command in all commands starts with "v", so you only need to type "v".

Because U-boot supports too many commands, it is necessary to clarify the usage of the U-Boot command first because of the development process. Next, explain the functions and parameters of these commands based on the help information for each command.

After entering the uboot command prompt, you can use the help command to know all the commands supported by the current uboot.

Help The name of the instruction, you can find the relevant help of the corresponding instruction, such as help setenv

The u-boot environment variable is used to store some of the frequently used parameter variables. uboot wants to store environment variables in static memory (such as nand nor eeprom mmc).

Some of them are also used frequently, and some are defined by the users themselves. There are errors in changing these names. In the following table, we list some common environment variables:

Bootdelay waits for the number of seconds to start automatically

Baudrate port console baud rate

Netmask mask of the Ethernet interface

NIC address of the ethaddr Ethernet card

Bootfile default download file

Bootargs startup parameters passed to the kernel

Command executed when bootcmd starts automatically

Serverip server ip address

Ipaddr local ip address

Stdin standard input device

Stdout standard output device

Stderr standard error device

These are the default environment variables that uboot exists. uboot itself uses these environment variables for configuration. We can define some environment variables for our own uboot driver to use.

The design logic of the Uboot environment variable is to read the env from the static memory into the RAM during the boot process, and then the operation of the env under the uboot (such as printenv editenv setenv) is the operation of the env in the RAM, only in the execution The env in RAM is rewritten into static memory when saveenv.

This design logic speeds up the reading and writing of env.

Somke Machine

Fog Smoke Machine

Feature:
* DURABLE MATERIAL: It is made of top grade aluminum alloy, built-in fan for heat dissipation, stable and lightweight. Look upscale and durable for long time.
* BEAUTIFUL COLOR SHOW: It can choose single colors or color combinations. It will be great enjoyment to see the colorful light projected to the ceiling, wall and floor,etc.
* SUIT FOR VARIOUS OCCASION: Suit for various parties, birthday, dance, holiday, celebrations, Karaoke, family or friend home celebration. The laser light can be used in home, disco, living room, bar, club, or anywhere needed.
* EASY OPERATION: The light will enter sound activated mode, which makes the lights blink according to the beat of the music or sound. Adjustable motion speed.
* CREAT ATMOSPHERE EVERYWHERE: This laser light is mini size with tripod, portable and convenient for carry. You can place it everywhere.


Our company have 13 years experience of LED Display and Stage Lights , our company mainly produce Indoor Rental LED Display, Outdoor Rental LED Display, Transparent LED Display,Indoor Fixed Indoor LED Display, Outdoor Fixed LED Display, Poster LED Display , Dance LED Display ... In additional, we also produce stage lights, such as beam lights Series, moving head lights Series, LED Par Light Series and son on..

Somke Machine Series,Smoke Machine,Wedding Smoke Machine,Smoke Machine Party

Guangzhou Chengwen Photoelectric Technology co.,ltd , https://www.cwleddisplay.com