• State TI Thinks Resolved
  • +1 person also asked this people also asked this
  • Locked Locked
  • Replies 9 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 217 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.

AM2434: API Usage for UART HW Flow Control

Hideaki Matsumoto
Genius 9070 points
Part Number: AM2434
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

Hi,

 

My customer is evaluating UART driver example “UART Echo Low Latency Interrupt” or “UART Echo Low Latency Polling” in MCU+ SDK 10.01.00.

 

They want to configure the UART as half-duplex with hardware flow control with enabling Auto_RTS_EN and disabling Auto_CTS_EN.

 

Could you share any example code with the above settings ?

Could you tell them how to configure for the above ?

 

They found some APIs and Parameters like UART_open(), UART_FCTYPE_HW, UART_FCPARAM_AUTO_RTS, UART_FCPARAM_AUTO_CTS, etc…

But they’re not sure how to use these APIs and parameters.

 

Thanks and regards,

Hideaki

  • 0
    TI__Mastermind 44926 points
    Hideaki Matsumoto said:
    They want to configure the UART as half-duplex with hardware flow control with enabling Auto_RTS_EN and disabling Auto_CTS_EN.

    Thanks for mentioning the requirement.

    Please have a look at the following highlighted section.

    Regards,

    Vaibhav

  • 0 in reply to Vaibhav Kumar
    TI__Genius 9070 points

    Hi Vaibhav,

    Thank you for your response. The following highlighted UART CTSn Pin or UART RTSn Pin seem to be PinMux configuration.

    If UART CTSn Pin above is unchecked, the AUTO_CTS_EN bit on UART_EFR register below is cleared ?

     

    Thanks and regards,

    Hideaki

  • 0 in reply to Hideaki Matsumoto
    TI__Mastermind 44926 points

    Thanks for your follow up response.

    I will check this in my setup by running UART application.

    Regards,

    Vaibhav

  • 0 in reply to Vaibhav Kumar
    TI__Genius 9070 points

    Thanks, Vaibhav.

    Please let me know once you could confirm it. It would be appreciated if we can receive it soon.

    Thanks and regards,

    Hideaki

  • 0 in reply to Hideaki Matsumoto
    TI__Mastermind 44926 points

    Hi,

    I have ran some experiments by modifying the HW flow control check option in SysConfig and checking/unchecking the CTS line as well.

    I have not seen in any of the cases the auto CTS enable bit being disabled, from 1 to 0.

    I am still trying to wrap the logic around when this is actually used and effective for communication.

    I will do my part on this and let you know once I have further updates.

    Regards,

    Vaibhav

  • 0 in reply to Vaibhav Kumar
    TI__Genius 9070 points

    Vaibhav,

    Thanks for your reply.

    Vaibhav Kumar said:

    I have ran some experiments by modifying the HW flow control check option in SysConfig and checking/unchecking the CTS line as well.

    I have not seen in any of the cases the auto CTS enable bit being disabled, from 1 to 0.

    If so, the first your answer is not correct for their question below ?

    Hideaki Matsumoto said:

    They want to configure the UART as half-duplex with hardware flow control with enabling Auto_RTS_EN and disabling Auto_CTS_EN.

     

    Could you share any example code with the above settings ?

    Could you tell them how to configure for the above ?

    Again, Could you please tell the customer how to disable Auto_CTS_EN.

    Thanks and regards,

    Hideaki

  • 0 in reply to Hideaki Matsumoto
    TI__Genius 9070 points

    Hi Vaibhav,

    The customer want to know how to disable Auto_CTS_EN by using API.
    Could you share the example code ?

    Actually, they tried to uncheck UART CTSn Pin(UART0_CTSn) by following your suggestion, but Data cannot be sent even though CTS is not connected. CTS seems to be enabled.
    On the other hand, they tried to check UART CTSn Pin(UART0_CTSn), then data was able to be sent.
    It looks a bug on SysConfig.
    Therefore, they want to know how to disable Auto_CTS_EN by using API.

    Thanks and regards,
    Hideaki

  • 0 in reply to Hideaki Matsumoto
    TI__Mastermind 44926 points
    Hideaki Matsumoto said:
    Therefore, they want to know how to disable Auto_CTS_EN by using API.

    I am not seeing any such API currently in the MCU PLUS SDK, allow me sometime to check more on this.

  • 0 in reply to Vaibhav Kumar
    TI__Mastermind 44926 points

    Hi Hideaki,

    On the latest SDK, I see that there is a check for HW flow control.

    Can you please ask the customer to refer the file uart_v0_lld.c

    Inside this file, there is a call made with the help of an API called: 

    UART_hardwareFlowCtrlOptSet
    This has an argument of 
    UART_RTS_CTS_ENABLE which basically says, both RTS and CTS is enabled.
    The macro 
    UART_RTS_CTS_ENABLE has a value of 3 which is 11b hence both CTS and RTS is enabled.
    We just want the RTS to be enabled, hence we have to simply pass the argument which is:
    UART_RTS_ENABLE
    So instead of the call being made as: 
     UART_hardwareFlowCtrlOptSet(baseAddr, UART_RTS_CTS_ENABLE);
    The call should rather be:
     UART_hardwareFlowCtrlOptSet(baseAddr, UART_RTS_ENABLE);
    Can you please propose this to the customer and let me know if it works for them?
    Looking forward to your response.
    Regards,
    Vaibhav