Introduction:
What is a single board?
The typical composition of the early microcomputer is 6 (or more) boards - inserted into a floor - performs a central processor unit (CPU), memory, disk controller, and serial / parallel port feature. These backplane-based microcomputers are used to acquire data, process control, and R & D plans, but usually the size is too large to be used as a smart embedded in the device.
In the early 1980s, the integrated circuit (IC) technology is advanced, and the function of the previous board can be integrated into a single "large proportional integration" (LSI) logical chip. The LSI chip of CPU, memory, memory, and serial / parallel ports can now actually perform the entire microcomputer system on a single board - no bottom plate. The Z80-based "big board" (1980) may be the first single board (SBC), which can run a commercial disk operating system (CP / M).
Embedded panel market
Similar to the large board, "Sub-board" (1983 AMPRO) uses Z80 CPU, the goal is the CP / M operating system. However, its size is much smaller, matches the script printing of the floppy disk drive (5.75 x 8.0). Due to its unique close combination, simple, reliable and low cost, the small board is suitable for commercial disk operating systems to simply embed non-their computer.
Therefore, it has created an embedded panel market, which is now crowded with hundreds of board machine manufacturers, and produces thousands of different board machine products for different embedded and specialized computing applications.
Initially, each single board product is completely unique - including structural and morphology. This is largely blamed on the intrinsic differences of embedded system requirements, combining various processors and available peripheral controllers. In addition, there is no standard to affect the functional selection and mechanical specifications of the board developer.
Generate a board compatible with PC
In the mid-1980s, people are increasingly interested in IBM PC compatibility in embedded and other non-desktop applications, because of two key factors:
Hardware leverage - PC chip sets and peripheral compatibility can produce lower cost, simpler, and more easily supported systems
Software leverage - PC compatibility makes it possible to utilize the PC's operating system (first MS-DOS, then Windows), language, tools, and application software.
Some of these thus generated PC compatible microcomputers are based on IBM PC ("" ISA "bus) plug-in card form factor. Some as a stand-alone system (no backplane) on a single board. There are also some adaptation to the architectural border bus (STD, VME).
In the case of an embedded non-final plate board, PC compatibility will soon become a trend. Most people agree to several popular morphological factors:
Small panel (5.75 x 8.0 in.) - Full system on a single compact board, extensible insertion function module
ISA "slot board" (full length 13.8 x 4.8IN; half length 7.1 x 4.8 in) - IBM PC plugin card version of the board (bottom plate) can be operated as a stand-alone board machine (no backplane)
PC / 104 module (3.6 x 3.8 in.) - Compact, high and low, self-hepoly module with reliable needle and socket board to plate expansion bus
With the arrival of PCI, I then added 10 years ...
PC / 104- plus -PCI increases to PC / 104
EBX - PC / 104 - Add to the small board
Not all board machines jumped into these popular morphological factors. They did not take PC compatibility (X86 / DOS / Windows) route. Throughout the dozens of history of the board computer, there will also continue to have a non-standard board size and a unique application requirement or to meet a small habitat structure that does not match standard morphological factors and popular "WINTEL" structures.
Drama change
Today, several important factors challenge the status quo of the board: outbreak the demand for embedded intelligence - even the least cost-effective products and equipment, they want to have at least fundamental embedded intelligence. Many also need to support / compatible with Linux graphics and / or voice interfaces.
Universally existing connections - Each electron is connected to each other (through wired or wireless), is growing. These devices must often be able to access the Internet connection and must support a large number of standardization protocols (TCP / IP, PPP, HTTP, FTP).
Expanded peripherals and bus interfaces - Although the popular interconnect criteria sometimes seems immortal, new interfaces continue to replace old. 20 years after almost born in PC, ISA bus finally replaced PCI. USB is replacing an old serial, parallel and PS / 2 port. The Ethernet can be seen everywhere, and FireWire (IEEE-1394) is also powerful. SCSI has never become the mainstream in the PC (except Apple). We can continue to move towards the expansion mechanism into the edge of the free floor system of the medium and high-speed serial interface (USB, IRDA, FIREWIRE, Ethernet ...).
Apply-oriented System-On-CHIP processor - a large number of highly integrated ONE-CHIP SYSTEMS-based ARM, MIPS, POWERPC, and X86 are being developed to match the specifications of various large capacity and cost-sensitive products. Now, these "Application-ON-CHIP" processors describe the material of new types of highly integrated, efficient and cost effective board machines. Some such a single board machine is not constrained x86 compatibility for cost / energy / comprehensive advantages.
Embedded Linux - In just a few years, Linux broke all aspects of the calculation scene, providing low-cost, open resource scenarios, support open standards, networks, communications, Internet, graphics, etc. In addition to the initial Unix clone, Linux now supports the same "traditional" embedded operating system as the processor. Therefore, the operating system that supports the full characteristics of different structures has increased in recent years, which is attributed to the performance and growth of Linux rapid evolution, thereby producing more competition in the competitive processor structure. .
Considering all of these factors, it is obvious that changing the conditions of the embedded panel market is mature! A little confusion theory
It is almost impossible to position two and other similar board machines before the embedded panel market combined with the PC structure and a small number of morphological factors. The PC structure brought the degree of command (several shapes and sizes) into chaos, as a unified force - lasts for 20 years.
Now, with the new interface (USB, FireWire, Bluetooth), Structure (MIPS, PowerPC, ARM), and Operating System (Linux), the embedded board market is better prepared to enter the new life cycle - - The initial manifestation is to improve the difference between the operating system, processor structure, peripheral interface, and physical morphological factors.
Here we introduce - Support / Compatible Linux Embedded Machine Vehicle Quick Reference Guide.
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Excerpt from:
Embedded Linux
