This paper mainly explains the difference between PCI bus and PXI bus. Firstly, it introduces the structure diagram, characteristics and performance of PCI bus, secondly expounds the characteristics of PXI bus, and finally introduces the difference between PCI bus and PXI bus.

PCI bus introduction

PCI bus is a tree structure, independent of CPU bus, and can operate in parallel with CPU bus. PCI devices and PCI bridges can be attached to the PCI bus. Only one PCI master device is allowed on the PCI bus, and the others are PCI slave devices. Moreover, the read-write operation can only be carried out between the master and slave devices, and the data exchange between the slave devices needs to be transferred through the master device.

PCI bus structure diagram

Characteristics and performance comparison between PCI bus and PXI Bus

PCI bus features

(1) The transmission rate is high, and the maximum data transmission rate is 132mb / s. when the data width is upgraded to 64 bits, the data transmission rate can reach 264mb / s. This is unmatched by other buses. It greatly alleviates the data I / O bottleneck, gives full play to the function of high-performance CPU, and meets the needs of data transmission of high-speed equipment.

(2) Multi bus coexistence PCI bus can allow multiple buses to coexist in one system and accommodate devices with different speeds to work together. The CPU bus and PCI bus are bridged through the host-pci bridging component chip; PCI bus and ISA / EISA bus are bridged by PCI-ISA / EISA bridging component chip to form a hierarchical multi bus system. The high-speed equipment is removed from the ISA / EISA bus and moved to the PCI bus. The low-speed equipment can still hang on the ISA / EISA bus, inherit the original resources and expand the compatibility of the system.

(3) Independent of CPU, PCI bus is not attached to a specific processor, that is, PCI Bus supports a variety of processors and new processors to be developed in the future. When changing the processor variety, replace the corresponding bridge components.

PCI bus performance

(1) The transmission rate is high, and the maximum data transmission rate is 132mb / s. when the data width is upgraded to 64 bits, the data transmission rate can reach 264mb / s. This is unmatched by other buses. It greatly alleviates the data I / O bottleneck, gives full play to the function of high-performance CPU, and meets the needs of data transmission of high-speed equipment.

(2) Multi bus coexistence PCI bus can allow multiple buses to coexist in one system and accommodate devices with different speeds to work together. The CPU bus and PCI bus are bridged through the host-pci bridging component chip; PCI bus and ISA / EISA bus are bridged by PCI-ISA / EISA bridging component chip to form a hierarchical multi bus system. The high-speed equipment is removed from the ISA / EISA bus and moved to the PCI bus. The low-speed equipment can still hang on the ISA / EISA bus, inherit the original resources and expand the compatibility of the system.

(3) Independent of CPU, PCI bus is not attached to a specific processor, that is, PCI Bus supports a variety of processors and new processors to be developed in the future. When changing the processor variety, replace the corresponding bridge components.

(4) Automatic identification and configuration of peripherals, convenient for users.

(5) Parallel operation capability.

Characteristics and performance comparison between PCI bus and PXI Bus

Introduction to PXI Bus

PXI is a rugged PC based measurement and automation platform. PXI combines the electrical bus characteristics of PCI with the firmness and modularity of CompactPCI and the mechanical packaging characteristics of Eurocard, and adds special synchronous bus and main software characteristics. This makes it a high-performance, low-cost delivery platform for measurement and automation systems. These systems can be used in various fields such as manufacturing testing, military and aviation, machine monitoring, automobile production and industrial testing.

PXI was developed in 1997 and officially launched in 1998. It is an open industrial standard to meet the increasing demand for complex instrument systems. Today, the PXI standard is managed by the PXI systems Alliance (pxisa). The alliance is composed of more than 60 companies that jointly promote PXI standards, ensure PXI interchangeability, and maintain PXI specifications.

Hardware architecture PXI system consists of three basic parts: chassis, system controller and peripheral module.

PXI is directly compatible with CompactPCI, so any 3U CompactPCI module can be directly used in PXI system. In addition, card / PCMCIA and PMC (PCI mezzanine card) cards can be directly inserted into the PXI system using the carrier module. For example, Ni pxi-8221 PC card carrier can connect CardBus and PCMCIA devices to PXI system.

Characteristics of PXI Bus

1. Newly added electrical packaging specificationIn addition to transplanting all mechanical specifications in CompactPCI specification directly into PXI specification, PXI also adds some requirements that CompactPCI does not have in order to simplify system integration. As mentioned earlier, the system slot in the PXI chassis must be located at the leftmost end, and the main controller can only be extended to the left to avoid occupying the instrument module slot. The PXI also specifies that the forced cooling air flow required by the module must flow from the bottom of the module to the top. The environmental tests recommended by PXI specification include temperature, humidity, vibration and impact tests on all modules, and the test results shall be provided in writing. At the same time, the PXI specification also specifies the operating and storage temperature range of all modules.

2. Interoperability with CompactPCI one of the important features of PXI is to maintain interoperability with standard CompactPCI products. However, the components required by many PXI compatible systems may not require complete PXI bus features. For example, a user may want to use a standard CompactPCI network interface module in a PXI chassis, or a PXI compatible module in a standard CompactPCI chassis. In these cases, users need the basic functions of the module rather than the complete PXI features.

Characteristics and performance comparison between PCI bus and PXI Bus

What is the difference between PCI bus and PXI bus

In 1997, National Instruments put forward a new solution for testing and measurement applications: PXI (PCI extensions for instrumentation) – CompactPCI optimized for testing tasks. In 1998, the PXI system alliance, which Ni cooperated with other test equipment manufacturers, introduced PXI to the market as an open industrial standard. Today, PXI has become the standard platform for testing, measurement and automation applications. Its open architecture, flexibility and cost advantages of PC technology have brought earth shaking reform to the measurement and automation industry.

PXI is a modular instrument platform specially customized for industrial data acquisition and automation applications, with mechanical, electrical, software and other professional characteristics. PXI makes full use of PCI, the most popular high-speed standard structure of desktop computer. PXI specification is an extension of CompactPCI specification. CompactPCI defines a rugged industrial PCI bus architecture, which provides excellent mechanical integration on the premise of easy loading and unloading of hardware modules.

Therefore, PXI products have higher level and more rigorous environmental consistency indicators, which meet the limit conditions of vibration, impact, temperature and humidity in industrial environment. PXI compulsorily adds environmental performance test and active cooling device to the mechanical specification of CompactPCI to simplify system integration and ensure interoperability between products of different manufacturers. In addition, PXI adds the special timing and trigger characteristics of measurement and automation system on the basis of high-speed PCI bus.

In general, PXI is a solid modular instrument platform. It puts forward a high-performance standardized measurement and automation scheme based on computer. Provide much better performance than the original system architecture at a reasonable price. PXI users naturally enjoy many conveniences, such as cheap, easy-to-use and flexible PC technology; Open industry standards and full interoperability with CompactPCI products.

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