机械毕业设计英文外文翻译20SJA1000独立的CAN控制器.docx

1、机械毕业设计英文外文翻译20SJA1000独立的CAN控制器附录A 英文原文SJA1000Stand-alone CAN controller1. INTRODUCTIONThe SJA1000 is a stand-alone CAN Controller product with advanced features for use in automotive and general industrial applications. It is intended to replace the PCA82C200 because it is hardware and software comp

2、atible. Due to an enhanced set of functions this device is well suited for many applications especially when systemoptimization, diagnosis and maintenance are important.This report is intended to guide the user in designing complete CAN nodes based on the SJA1000. The report provides typical applica

3、tion circuit diagrams and flow charts for programming.2. OVERVIEWThe stand-alone CAN controller SJA1000 1 has two different Modes of Operation:1.BasicCAN Mode (PCA82C250 compatible).2.PeliCAN Mode.Upon Power-up the BasicCAN Mode is the default mode of operation. Consequently, existing hardware and s

4、oftware developed for the PCA82C250 can be used without any change. In addition to the functions known from the PCA82C250 , some extra features have been implemented in this mode which make the device more attractive. However, they do not influence the compatibility to the PCA82C250.The PeliCAN Mode

5、 is a new mode of operation which is able to handle all frame types according to CAN specification 2.0B. Furthermore it provides a couple of enhanced features which makes the SJA1000 suitable for a wide range of applications.2.1 SJA1000 FeaturesThe features of the SJA1000 can be clustered into three

6、 main groups:1.Well-established PCA82C200 FunctionsFeatures of this group have already been implemented in the PCA82C250.2.Improved PCA82C200 FunctionsPartly these functions have already been implemented in the PCA82C250. However, in the SJA1000 they have been improved in terms of speed, size or per

7、formance.3.Enhanced Functions in PeliCAN ModeIn PeliCAN Mode the SJA1000 offers a couple of Error Analysis Functions supporting diagnosis, system maintenance and optimization. Furthermore functions for general CPU support and System Self Test have been added in this mode.2.2 CAN Node ArchitectureGen

8、erally each CAN module can be divided into different functional blocks. The connection to the CAN bus linesis usually built with a CAN Transceiver optimized for the applications. The transceiver controls thelogic level signals from the CAN controller into the physical levels on the bus and vice vers

9、a.The next upper level is a CAN Controller which implements the complete CAN protocol defined in the CAN Specification 8. Often it also covers message buffering and acceptance filtering.All these CAN functions are controlled by a Module Controller which performs the functionality of the application.

10、 For example, it controls actuators, reads sensors and handles the man-machine interface (MMI).As shown in Figure 1 the SJA1000 stand-alone CAN controller is always located between a microcontroller and the transceiver, which is an integrated circuit in most cases.Figure 1 CAN Module Set-up2.3 Block

11、 DiagramThe following figure shows the block diagram of the SJA1000.The CAN Core Block controls the transmission and reception of CAN frames according to the CAN specification.The Interface Management Logic block performs a link to the external host controller which can be a microcontroller or any o

12、ther device. Every register access via the SJA1000 multiplexed address/data bus and controlling of the read/write strobes is handled in this unit. Additionally to the BasicCAN functions known from the PCA82C250, new PeliCAN features have been added. As a consequence of this, additional registers and

13、 logic have been implemented mainly in this block.Figure 2: Block Diagram SJA1000The Transmit Buffer of the SJA1000 is able to store one complete message (Extended or Standard). Whenever a transmission is initiated by the host controller the Interface Management Logic forces the CAN Core Block to re

14、ad the CAN message from the Transmit Buffer.When receiving a message, the CAN Core Block converts the serial bit stream into parallel data for the Acceptance Filter. With this programmable filter the SJA1000 decides which messages actually are received by the host controller.All received messages ac

15、cepted by the acceptance filter are stored within a Receive FIFO. Depending on the mode of operation and the data length up to 32 messages can be stored. This enables the user to be more flexible when specifying interrupt services and interrupt priorities for the system because the probability of da

16、ta overrun conditions is reduced extremely.3. SYSTEMFor connection to the host controller, the SJA1000 provides a multiplexed address/data bus and additional read/write control signals. The SJA1000 could be seen as a peripheral memory mapped I/O device for the host controller.3.1 SJA1000 ApplicationConfiguration Registers and pins of the SJA1000 allow to use all kinds of integrated or discrete CAN transceivers. Due to