• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 82 subscribers
  • Views 455 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.

Original question:

TMS320F28335: F28335: Question regarding eCAN - CANRFP

TMS320F28335: F28335 eCAN - CANES

Henrique T.
Intellectual 490 points
Part Number: TMS320F28335


In SPRUEU1, topic 2.13 (CANES) is said that one should write 1 to clean (acknowledge) the error flags.

The bits FE, BE, CRCE, SE, ACKE, BO, EP, EW are all R/C (Read/Clear) type, according to Figure 2-13.

But at Table 2-13, only  FE & BE are explicitly called "flags". 

So, my question is about CRCE, SE, ACKE, BO, EP & EW bits. They aren't explicitly treated as flags and there aren't any explanation about how to clean them.

But they are R/C bits and their functions can be understood as flags.

So, I clean them by writting 1, as with FE & BE?

Additionally, if it is not detailed in the text, can I infer that all bits of  RC type must be cleaned by writing 1 and all RW bits must be cleaned by writting 0?... for all TMS320F28335 peripherals?

  • 0
    TI__Expert 7985 points
    Hi Henrique,

    The literature states the following:

    "If one of these error flags is set, then the current state of all other error flags is frozen. i.e. Only the first error is stored. In order to update the
    CANES register subsequently, the error flag which is set has to be acknowledged by writing a 1 to it. This action also clears the flag bit."

    You are right, All RC type bits must be cleared by writing a 1. You are actually acknowledging that you are "read and may be recorded" the system state by writing a '1'. The act of acknowledging has the side effect of clearing the bit, by design, so that it is ready and available to record/report the system status if and when the condition occurs again.

    You are right about the RW bits as well. However, RW bits are usually for configuration and control of the system and not for system status and error reporting. So for configuration and control you would typically turn something ON by writing a 1 and turn it OFF by writing a 0.

    Thanks,
    Krishna
  • 0 in reply to Krishna Allam
    Intellectual 490 points
    Perfect answer. Thanks