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Linux/TCAN4550: About CAN Driver issue and HW Design

yimin bai34
Genius 4755 points
Part Number: TCAN4550
Other Parts Discussed in Thread: AM3352

Tool/software: Linux

Hi SIr 

We have referred to the Linux driver code TI offered and have some questions as below 

PS: We used AM3352 platform and want to integrate TCAN4550 IC

Q1: It is necessary to use nWKRQ  pin ? or we can ignore it ? 

Q2: for INT0 and INT1 -> they are just two available interrupt lines. we can select for each interrupt flag whether it should be reported via INT0 or INT1.

        We need to design HW and want to check if GPIO1 should be set GPO by default and set the function as MCAN_INIT1 by default.

        We don't need to set it as GPI if we don't need watchdog function.

Q3: for linux driver -> m_can_fw_rewrite branch

      we don't see any example about application code like socketCAN or how to call API or Baudrate setting? 

      http://processors.wiki.ti.com/index.php/AM335X_DCAN_Driver_Guide

      Will TI update this section or other suggestion ?

      BTW, we used SDK6.0(kernel 3.2) for development and saw the driver is based on kernel 5.0.

BR

Yimin

  • 0
    TI__Intellectual 2090 points
    Hi Yimin,

    Thank you for your questions. See my feedback below:

    1. The nWKRQ pin is not necessary for you to monitor. We have provided that output as an added optional feature for your software use should you choose.

    2. I'm not sure what you mean by INT1 and INT2. Do you mean GPIO1 and GPO2? The TCAN4550 has only one dedicated interrupt pin, NINT. The GPIO1 and GPO2 pins are configurable for multiple purposes. Just want to clarify.
    The GPIO1 pin does indeed default to an output, and the output defaults to the MCAN_INT1 interrupt. This can be seen from Table 15: Modes of Operation and Pin Configuration Registers Field Descriptions in the datasheet.

    3. Let me confer with the engineer that developed the example code. I will get back to you shortly on this one.


    Best Regards,
    Max Megee
    TI Transceiver Interface
  • 0 in reply to Max Megee
    Intellectual 265 points
    Hi Sir

    One more question

    Do we need GOIO1 and GPIO2 Pin for connection?
    Or we can ignore it ?

    BR
    Yimin
  • 0 in reply to yimin bai
    TI__Intellectual 2090 points
    Hi Yimin,

    Again, you are not required to use the GPIO1 and GPO2 pins. However, you will be unable to access some of the features of the TCAN4550 if you elect to disregard those pins. You will be unable to use or service the TCAN4550 watchdog. You will also lose the ability to test the TCAN4550 in transceiver test mode or controller test mode. GPIO1 can also give you some quick insight into a thermal or under voltage fault, or one of the MCAN interrupts.
    Again, it is not required for you to monitor these pins, but there are multiple features that could be useful for your setup as you wish to use them.

    Best Regards,
    Max
  • 0 in reply to Max Megee
    Genius 4755 points

    Hi Sir

    Do you have any update for item 3 

    thanks 

    BR

    Yimin

  • 0 in reply to yimin bai34
    TI__Intellectual 2090 points

    Hi Yimin,

    We currently do not have any published updates for example application code for which you have asked.   The linux driver should have functions for baud rate setting and API, but you will need to develop the code for implementing those function calls.  Unfortunately we are not planning to develop code for software drivers other than what we have provided already.  We know that each application will require some some software development and fine tuning specific to each end-use.  

    Are there any other hardware-specific questions that I can help with?  

    Best Regards,

    Max