怎么在FPGA中制作CAN BUS***器

任何人？



以下为原文

Anyone?

目前尚不清楚您想回答什么问题。
你已经说过你已经“制造”了一个VGA控制器和一个PCI控制器。
您认为计划设计的哪些部分会给您带来问题？
我猜测一小部分FPGA设计人员（和用户论坛通讯员）在详细级别上熟悉CAN总线协议和接口。
如果您对您的请求更具体，您可能更有可能收到有用的回复。
- 鲍勃埃尔金德
签名：新手的自述文件在这里：http：//forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369总结：1。
阅读手册或用户指南。
你读过手册了吗？
你能找到手册吗？2。
搜索论坛（并搜索网页）以寻找类似的主题。
不要在多个论坛上发布相同的问题。
不要在别人的主题上发布新主题或问题，开始新的主题！5。
学生：复制代码与学习设计不同.6“它不起作用”不是一个可以回答的问题。
提供有用的详细信息（请与网页，数据表链接）.7。
您的代码中的评论不需要支付额外费用。
我没有支付论坛帖子的费用。
如果我写一篇好文章，那么我一无所获。



以下为原文

It is not clear what question you would like answered.
 
You have said that you have already "made" a VGA controller and a PCI controller.
What parts of your planned design do you think will pose problems for you?
 
I am guessing that a small fraction of FPGA designers (and user forum correspondents) are familiar with CAN bus protocol and interfaces on a detailed level.  If you can be more specific with your request, you may be more likely to receive a useful reply.
 
-- Bob Elkind
SIGNATURE:
README for newbies is here: http://forums.xilinx.com/t5/New-Users-Forum/README-first-Help-for-new-users/td-p/219369

Summary:
1. Read the manual or user guide.  Have you read the manual? Can you find the manual?
2. Search the forums (and search the web) for similar topics.
3. Do not post the same question on multiple forums.
4. Do not post a new topic or question on someone else's thread, start a new thread!
5. Students: Copying code is not the same as learning to design.
6 "It does not work" is not a question which can be answered. Provide useful details (with webpage, datasheet links, please).
7. You are not charged extra fees for comments in your code.
8. I am not paid for forum posts.  If I write a good post, then I have been good for nothing.

我们在某些产品中使用CAN，但这不是我工作过的领域。但是，查看配备CAN的电路板的原理图，PHY（物理接口层）可确保您正确使用。
我们似乎在CANbus和FPGA之间使用变压器，终端电阻和收发器IC。
我怀疑你最喜欢的互联网搜索引擎会找到合适的收发器IC和应用笔记。
根据现行标准，接口速度很慢，但是广泛的协议选择可能使“通用”嗅探器的设计非常耗时。
------------------------------------------“如果它不起作用
模拟，它不会在板上工作。“



以下为原文

We use CAN in some of our products, but this is not an area I have worked in. However, looking at the schematics for a CAN-equipped board, the PHY (physical interface layer) is something to ensure that you get right. We seem to use a transformer, a termination resistor, and a transceiver IC between the CANbus and the FPGA. I suspect that your favourite Internet search engine will find a suitable transceiver IC and application notes.

The interface is slow by current standards, but the wide selection of protocols could make the design of a 'universal' sniffer quite time-consuming.
------------------------------------------
"If it don't work in simulation, it won't work on the board."

嗨！
我想将CAN transciever（例如：http：//www.maxim-ic.com/datasheet/index.mvp/id/4299）连接到CAN控制器（例如：http：//ww1.microchip.com/
downloads / en / devicedoc / 21801d.pdf）和CAN控制器到FPGA。
在FPGA内部，我想实现SPI总线与CAN控制器通信，UART总线与PC通信，因此我可以在PC上看到CAN消息。
首先 - 这是否可能 - 我在想什么？
然后 - 据我所知，FPGA板（我的是Digilent的Spartan 3E：http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,792&Prod=S3EBOARD）工作在3.3V电压。
..所以CAN收发器和CAN控制器都需要工作在3.3V，对吗？
接下来的事情 - 因为我对模拟电子产品一无所知......将CAN收发器和CAN控制器连接到FPGA板是否需要任何模拟元件，或者只是使用电线？
我可以使用FPGA的时钟来驱动CAN控制器吗？
总线速度 - 由于CAN比UART快，我在CAN网络上实时跟踪数据包会有问题吗？
非常感谢您提前的答案！



以下为原文

Hi!
 
I would like to connect CAN transciever (for example: http://www.maxim-ic.com/datasheet/index.mvp/id/4299) to CAN controller (for example: http://ww1.microchip.com/downloads/en/devicedoc/21801d.pdf) and CAN controller to FPGA. Inside FPGA, I would like to implement SPI bus to talk to  the CAN controller, and UART bus to talk to the PC, so I can see the CAN messages on PC.
 
First of all - is this even possible - am I thinking right?
 
Then - as far as I know, the FPGA board (mine is Spartan 3E from Digilent: http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,792&Prod=S3EBOARD) works on 3.3V voltage ... so both CAN transciever and CAN controller need to work on 3.3V, am I right?
 
Next thing - since I don't have knowledge in analog electronics ... is there any analog component needed to connect CAN transciever and CAN controller to the FPGA board, or is it enought just to use wires? Can I use clock from FPGA to drive the CAN controller?
 
Bus speeds - since CAN is faster than UART, will I have problems following packets in real time on CAN network?
 
 
Thank you very much for your answers in advance!

快速印象：1。
CAN收发器看起来是一个不错的选择。
我不打算使用CAN控制器，因为你想要的只是一个非传输的监视器/嗅探器。
您可能需要一个软件元素来解码协议，例如MicroBlaze，使用XPS / EDK /等等。
用HDL做这一切都是可能的，但可能真的很难。
MB SystemBuilder将允许您添加UART。
电路板原理图的第2页显示了RS232收发器。
您将需要四处寻找模拟电路，或者希望其他人能够帮助您解决问题。
但是，如果要说明需要监控哪种设备，那将会有很大帮助。
可能会有所帮助：http：//www.can232.com/或者是否会作弊？
------------------------------------------“如果它不起作用
模拟，它不会在板上工作。“



以下为原文

Quick impressions:
1. The CAN Transceiver looks like a good enough choice.
2. I wouldn't bother with a CAN Controller, as all you want is a non-transmitting monitor/sniffer.
3. You will probably need a software element to decode the protocol, for example a MicroBlaze, using XPS/EDK/whatever. Doing it all in HDL would be possible, but probably really hard. The MB SystemBuilder will allow you add a UART. Sheet 2 of the board schematics shows a RS232 transceiver.
4. You will need to dig around for the analogue circuitry, or hope sombody else bothers to help you out. HOWEVER, it would help a lot if you were to state what sort of equipment you need to monitor.
5. What might help is: http://www.can232.com/ Or would that be cheating?
 

------------------------------------------
"If it don't work in simulation, it won't work on the board."

嗨！
首先，感谢您的回答！
1）关于CAN控制器 - 是的，我不会在CAN总线上传输任何数据，我只需要“嗅”CAN总线上发生的事情......
这是否意味着我只能使用CAN收发器？
我最关心的是 -  CAN收发器的输出是什么类型的数据（在rx和tx线路上）？
2）关于协议解码。
我以为硬件部分只会通过UART向PC发送原始信息（例如0和1）。
我会用软件（我自己的）处理协议解码。
3）是的，can232绝对会作弊。
;）这个项目的重点是我自己建立嗅探器...我知道“已经工作的”是便宜的。
4）我想监控汽车系统上的CAN总线。
实际上，我想将我的嗅探器连接到汽车上的OBD端口并将数据记录在总线上。



以下为原文

Hi!
 
First of all, thanks for your answers!
 
1) About CAN controller - Yes, I will not be transmitting any data on CAN bus, I only need to "sniff" what on CAN bus is going on ...
 
Does this mean I can only use CAN transciever? My biggest concern is - what kind of data is the output of the CAN transciever (on rx and tx lines)?
 
2) About protocol decoding. I was thinking that the hardware part would only be sending raw information (e.g. zeros and ones) over UART to the PC. I would handle protocol decoding with software (my own).
 
3) Yes, can232 would definately be cheating. ;) The whole point of this project is to build the sniffer on my own ... I know the "already working ones" are cheap to buy.
 
4) I would like to monitor CAN bus on automotive systems. Practically, I would like to connect my sniffer to OBD port on a car and record the data on the bus. 

jcerna1写道：
你好！
首先，我想说我是FPGA的初学者。
到目前为止，我已经在Spartan 3 FPGA上制作了简单的VGA和PCI控制器，这基本上都是我的经验。
但是，我想在FPGA中制作CAN BUS嗅探器。
我只想看到总线上传递的消息，没有其他高级功能。
我正在考虑将CAN收发器连接到FPGA板，然后通过UART将解码的消息发送到PC。
现在 - 因为我是初学者 - 有人可以评估这个项目有多难吗？
有人可以分享任何提示吗？
谢谢！
FWIW，如果我必须建立一个CAN总线嗅探器，我会使用一个内置CAN总线接口的微控制器。
----------------------------是的，我这样做是为了谋生。



以下为原文

jcerna1 wrote:
Hello!
 
First of all, I would like to say I am beginner in FPGA. I have made simple VGA and PCI controller on Spartan 3 FPGA so far, that's basically all my experience.
 
However, I would like to make CAN BUS sniffer in FPGA. I would only like to see the messages passing on the bus, no other advanced functions. I was thinking about connection CAN transceiver to the FPGA board and then to send the decoded messages to PC via UART.
 
Now - since I am beginner - can somebody evaulate how difficult would this project be? Could somebody share any tip?
 
Thanks!

FWIW, if I had to build a CAN bus sniffer, I'd use a microcontroller with a built-in CAN bus interface.
----------------------------Yes, I do this for a living.

你能说得更具体吗？
在这种情况下，FPGA将扮演什么角色？



以下为原文

Could you be more specific why? What part would FPGA play in this case?

jcerna1写道：
你能说得更具体吗？
在这种情况下，FPGA将扮演什么角色？
你回答给谁？
----------------------------是的，我这样做是为了谋生。



以下为原文

jcerna1 wrote:
Could you be more specific why? What part would FPGA play in this case?

To whom are you replying?
----------------------------Yes, I do this for a living.