Software and Hardware Design for an embedded Linux platform

The software and hardware design of an embedded Linux platform-general Linux technology-Linux programming and kernel information. The following is a detailed description. 1. uClinux

Linux is a popular UNIX-like operating system. It is free and open source code and is widely used in personal computers and servers. More importantly, Linux adopts modular design and can be customized in practical applications. Therefore, Linux is also applicable to the embedded field. UClinux is an embedded version of Linux. Its kernel binary image file can be smaller than kb.

UClinux is designed for the Memory-free MMU (Memory Management Unit) processor. It supports multiple tasks, a complete TCP/IP protocol stack, and multiple network protocols. UClinux also supports multiple file systems, such as ROMFS, NFS, and FAT16/32. In fact, uClinux has been successfully applied to vrouters, network cameras, set-top boxes, PDAs, and many other fields.

In addition, uClinux is highly portable. By reconfiguration and compiling the kernel, you can easily transplant it to a variety of computing platforms such as 68 K, Dragon Ball, ColdFire, Power PC, and ARM. Currently, uClinux provides two kernel versions: 2.0 and 2.4. Since kernel version 2.2, Linux has been designed to be compatible with the ieee posix standard, which means most of the existing UNIX programs, the source code can be compiled and transplanted to the new target platform without modification. I chose the 2.4 kernel uClinux as the platform operating system.

2. Hardware Platform Design

2.1 Processors

The CPU of the target platform uses the ColdFire embedded processor MCF5272 produced by Motorola. MCF5272 adopts ColdFfireV2 variable-length CPU core and DigitalDNA technology, which can achieve excellent processing capability of 63MIPS@Dhrystone2.1 at 66MHz clock. Its internal SIM (System Integrated Module) Unit integrates a wide range of general modules, such as 10/100 Mbps Fast Ethernet controller, USB interface, etc, moreover, it can be seamlessly connected to common peripheral devices (such as SDRAM and ISDN transceiver), which simplifies the design of peripheral circuits and reduces product costs, volumes, and power consumption.

2.2 system memory

The system memory is composed of three parts. MCF5272 is integrated with 4 K-byte SRAM (static RAM), extended off-chip FLASH (FLASH memory), and SDRAM (synchronous dynamic RAM ). The FLASH capacity is 1 Mbit/s x 16 bit, AMD29LV series, and the chip selection signal is CS0, which is used to store vector tables, uClinux kernel images, and ROMFS file systems. The 6-Bit Memory consists of 16 MB and 32-Bit Memory. The signal of the SDRAM chip selection is CS7.

2.3 General peripherals

MCF5272 is integrated with UART and USB controllers. Two RS232 serial ports and a USB Slave interface can be implemented with only a few peripheral chips. MCF5272 is also embedded with a FEC (Fast Ethernet controller), and an LXT971 is extended out of the chip to conveniently implement an Ethernet interface with a 100/10 Base T.