• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 83 subscribers
  • Views 587 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F28069: About TMS320F28069 CAN data read

user4290001
Intellectual 620 points
Part Number: TMS320F28069


Dear,

   My applicaiton is EV Air Conditoner and will used TI TMS320F28069. And My CAN transciever is TJA1051.

   As I know, CAN data will automatic be read by register. And I will read the data from the regiter.  We will use interrupt to read the register as usual，but I don't use it, I use the uncertain cycle to read. The cycle may be 10ms 、50ms or others. 

    In my application, I read CAN data is bit by bit.  So I will meet below question：

    When I don't  finish the whole frame（8bit）reading, may be only 3bit or 4bit, the next frame will come and will erases current frame. So I can't read complete frame. It may bing wrong information to the system. So could  you kindly help give some advice to avoid the problem? Great thx.

  • 0
    Genius 3215 points

    CAN messages are received periodically in certain intervals, depends on the structure of the transmitter (software and hardware) and your application. You need to use interrupt to read the received messages or read the Rx buffer in a predefined cycle. If you're taking the second approach, your reading intervals should be less than the transmitter interval or you will lost some packets. 

    Why don't you use the interrupt? you can easily use the interrupt and read the received message and store it, then your main routine can access the stored data at slower intervals.

    --Kash

    If my post answered your question, please click on "Verified Answer". 

  • 0 in reply to Kash Olia
    TI__Guru* 95315 points

    Hello,

                Answer to your question(s) depend a lot on your system, specifically how often messages are transmitted on the CAN bus. But first, we need to get the terminologies correct:

     

    "CAN data will automatic be read by register" --> CAN data will be automatically copied into the mailbox configured to receive that data.

     

    If you are concerned that mailbox data will be overwritten before you read it completely, you could activate the Overwrite-Protection-Control (OPC) mechanism. Please see the User guide for more details.