1. Definition of embedded system
Application-centric, computer technology-based, and software and hardware can be cut down to meet the application system's strict requirements for function, reliability, cost, volume, and power consumption.
2. The composition of the embedded system
Hardware part: embedded microprocessor, peripheral hardware equipment;
Software part: embedded operating system, specific application program.
Embedded microprocessor
Peripheral devices refer to other components other than embedded processors that perform auxiliary functions such as storage, communication, debugging, and display in an embedded system. According to the functions of peripheral devices, they can be divided into the following three categories:
(1) Memory: SRAM, DRAM, NAND FLASH, NOR FLASH, etc .;
(2) Interfaces: parallel port, RS232 serial port, SPI serial interface, USB universal serial bus, Ethernet interface, etc .;
(3) Human-machine interface: LCD, touch screen, keyboard, etc.
Embedded operating system
3. Characteristics of embedded system
Comparison of embedded system and ordinary PC:
Boot sequence
The boot sequence of the embedded system:
The boot sequence of the PC:
4. Development process of embedded system
The embedded development steps based on Linux system are as follows:
1. Development of target hardware system: such as selection of microprocessor, Flash and other peripherals;
2. Establish a cross-development environment: install a cross-compilation tool chain (such as arm-linux-gcc), install development and debugging tools, set environment variables, configure serial communication tools (such as hyperterminal, SecureCRT, etc.), and configure network communication tools (such as NFS), configure Samba server, etc .;
3. Develop Bootloader: transplant uboot and vivi;
4. Linux kernel transplantation: such as Linux 2.6.8 kernel;
5. Develop root file system: such as cramfs, yaffs, etc .;
6. Develop drivers for related hardware: led, adc and other drivers;
7. Develop upper-layer applications: such as QT GUI development.
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