Computer Motherboard bus technology basics

Computer Motherboard bus technology basics

Any of a microprocessor to be with the number of components and peripheral devices to connect, but if each of the various components and peripherals
Prepared respectively by a group of lines directly connected with the CPU, then the connection will be complex, even difficult to achieve.
In order to simplify
Hardware circuit design, simplify the system structure, a set of commonly used lines, configure the appropriate interface circuit, with various components and peripherals
Preparation of connections, this group of lines is called sharing the connection bus. Bus structure used to facilitate the expansion of parts and equipment, in particular, to develop
A unified bus standard is likely to achieve the interconnection of different devices.
—- Microcomputer generally have internal bus in the bus, system bus and external bus. Internal bus is the internal microcomputer chip and the peripheral
Between the processor bus for chip-level interconnect; while the system bus is a computer in each plug-in board and system board between the total
Line for the plug-in board-level interconnect; external bus is a computer and external devices bus, microcomputer as a device,
Through the bus and other devices for information and data exchange, it is used for device-level interconnect.
—- In addition, broadly speaking, the computer means of communication can be divided into parallel communication and serial communication, and the corresponding communication bus is
Referred to as a parallel bus and serial bus. Fast parallel communication, real-time good, but because they are occupying the mouth lines and more unfit for a small
Chemical products; and serial communication rate was low, but the data communications throughput is not large in the micro-processing circuit is even more simple
Easy, convenient and flexible. Serial communication in general can be divided into asynchronous mode and synchronous mode.
—- With the microelectronics and computer technology, bus technology is continually developing and improving, leaving the total computer
Line technology varies widely, with different features. The following types of bus-only computer currently popular bus technology were to be referred
Shao.
1, the internal bus
—- 1. I2C-bus
—- I2C (Inter-IC) bus more than 10 years ago by the Philips company introduced in recent years, a broad field of communication control in microelectronics
Adopted a new type of bus standard. It is a special form of synchronous communication with interface cable less control method simplified,
The device package is small, the advantages of a higher communication speed. In the master-slave communication, you can have multiple I2C devices on the bus at the same time received a
I2C bus, through the address to identify the communication objects.
—- 2. SPI Bus
—- Serial peripheral interface SPI (serial peripheral interface) bus technology is Motorola has introduced a
Synchronous serial interface. Motorola produced the vast majority of MCU (micro-controllers) are equipped with SPI hardware interface, such as the
68 Series MCU. SPI bus is a three-wire synchronous bus, because of its strong hardware functions, therefore, with the SPI-related soft –
Piece is quite simple, so that more CPU time to handle other matters.
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—- 3. SCI Bus
—- Serial communication interface SCI (serial communication interface) is introduced by the Motorola Corporation. It is a
Kinds of universal asynchronous communication interface UART, and MCS-51 of the asynchronous communication function basically the same.
2, system bus
—- 1. ISA Bus
—- ISA (industrial standard architecture) bus standard is the IBM Corporation in 1984 for the introduction of PC / AT machine built
Li’s system bus standard, also called the AT bus. It is the XT expansion bus to accommodate the 8 / 16 bit data bus to be
Demand. 80286-80486 times it is widely used, so that now the Pentium machine also retain ISA bus slot.
ISA bus has 98 pins.
—- 2. EISA bus
—- EISA bus is in 1988 by Compaq and other nine co-launched bus standard. It is the base ISA bus
That basis the use of double-socket, in the original ISA bus 98 signal lines were added to 98 signal lines, that is, two
ISA added between the signal lines of an EISA signal line. In the utility of, EISA bus is fully compatible with ISA bus signals.
—- 3. VESA Bus
—- VESA (video electronics standard association) bus is the annex in 1992 by the 60 card manufacturer Joint
Launch of a local bus, referred to as the VL (VESA local bus) bus. It is the introduction of the microcomputer system bus architecture
Laid the foundation for innovation. The bus system taking into account the CPU and main memory and the Cache directly connected to this part is usually the total
Line known as the CPU bus or host bus, other equipment through the VL bus and CPU bus connected to, it is known as the VL-bus
Local bus. It defines a 32-bit data lines, and can be extended to a 64-bit expansion slot, use the 33MHz clock frequency,
Maximum transfer rate up to 132MB / s, can be synchronized with the CPU work. Is a high-speed, efficient local bus to support 386SX,
386DX, 486SX, 486DX and Pentium microprocessors.