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UART2 on Stellaris Launchpad

Robert Guastella
Prodigy 130 points


Hello,

I've tried to setup UART2 (PD6 & PD7) on an EK-LM4F120XL REV B Launchpad eval board. I've set the port up for transmit and receive interrupts, which are working. However, when I look at the transmit pin (PD7) I don't see any serial packets being transmitted. I'm wondering if it's possible to use PD6 & PD7 on the eval board? I don't have much of an I/O selection since I'm using the Kentec LCD touchscreen display, which is consuming a lot of I/O.


Here is a clip of my serial initialization routine:

    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART2);

    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

   GPIOPinConfigure(GPIO_PD6_U2RX);

   GPIOPinConfigure(GPIO_PD7_U2TX);

   UARTStdioInit(2);

   UARTFlowControlSet(GPIO_PORTD_BASE, UART_FLOWCONTROL_NONE);

// Enable the UART interrupt.

   UARTFIFODisable(UART2_BASE);

   ROM_IntEnable(INT_UART2);

   ROM_UARTIntEnable(UART2_BASE, UART_INT_RX | UART_INT_TX);

 

  • 0
    Guru 117855 points

    Again & again - dreaded PD7 default to NMI - claims new victim!

    MCU manual outlines this behavior (GPIO Section).  While bit of a burden - RTFM often helps when behavior is outside expectation...

    This pin - and one other - must be "unlocked" to be freed for your purpose...  Many posts this forum further detail...  (and bet you won't make this mistake - near future...)

    Note further you GPIOPinConfigure() both PD6 & PD7.  After the "unlock" - this is good.  Might you need GPIOPinType() - those 2 pins - as well?

    IMHO - examples which use Port_0 for UART - and in so doing exploit "default UART Port_0 behavior" (minus adequate warning) - lead new users down this twisted path...

  • 0 in reply to cb1_mobile
    Mastermind 7025 points

    cb1_mobile said:

    Again & again - dreaded PD7 default to NMI - claims new victim!

    MCU manual outlines this behavior (GPIO Section).  While bit of a burden - RTFM often helps when behavior is outside expectation...

    This pin - and one other - must be "unlocked" to be freed for your purpose...  Many posts this forum further detail...  (and bet you won't make this mistake - near future...)

    Note further you GPIOPinConfigure() both PD6 & PD7.  After the "unlock" - this is good.  Might you need GPIOPinType() - those 2 pins - as well?

    IMHO - examples which use Port_0 for UART - and in so doing exploit "default UART Port_0 behavior" (minus adequate warning) - lead new users down this twisted path...

    Maybe a common starting mistakes with TIVA/STELLARIS post would be more than useful.

    Searching in a forum, to get a snip of data is like looking for a fish in the sea....you get it if you know where to look for it.

    BTW, I do think TI may provide a better way to provide tech support than a forum.

    Regards

  • 0 in reply to PAk
    Guru 47900 points

    PAk SY said:
    Starting Mistakes with TIVA/STELLARIS post would be more than useful.

    Surely - long & hard this reporter has "begged/suggested" that such "keys" appear atop the forum - highlighted in RED!  (at least - past "everything in red" - has departed)  Might it be that such "alerts" may be seen to "damage" Sales - thus are suppressed?

    PAk SY said:
    like looking for a fish in the sea....you get it if you know where to look for it.

    Colorful and spot on - mon ami.  But - in which field (law, art, music etc.) does this not hold true?  And - being a good "investigator" (not a researcher!) pays huge dividends.   (just try declaring "research" as expense deduction - Gov't has very strict interpretation - and all U.S. schools (but for law) further corrupt this usage daily...)

    PAk SY said:
    I do think...may provide a better way to provide tech support than a forum.

    As you have such thought - care to share?  Promise to fairly review - comment. 

    Key posts here are "visited" in the K's - single helpful post may aid the multitudes - is not that wonderfully efficient?

    Our group has employed ARM nearing 10 years now.  (clients yelled for improved MCU performance - our products)  Active on many forums - for some time - none come close to vendor's efforts here.

    Do applaud your making the time/effort to opine - we inmates far outnumber asylum staff - constructive comments have met w/some past success...  (other than NRND M3 debacle...)

     

  • 0 in reply to cb1
    Mastermind 7025 points

    cb1- said:

    I do think...may provide a better way to provide tech support than a forum.

    As you have such thought - care to share?  Promise to fairly review - comment. 

    Key posts here are "visited" in the K's - single helpful post may aid the multitudes - is not that wonderfully efficient?

    Our group has employed ARM nearing 10 years now.  (clients yelled for improved MCU performance - our products)  Active on many forums - for some time - none come close to vendor's efforts here.

    Do applaud your making the time/effort to opine - we inmates far outnumber asylum staff - constructive comments have met w/some past success...  (other than NRND M3 debacle...)

    [/quote]

    I am not afraid of sharing at all .... in fact:

    http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/285768.aspx

    I was only pointing, that maybe TI may expend more resources in giving first AIDs here, than just waiting for external staff to solve the doubts of the newcomers.

    Of course I find invaluable the ability to search some useful specific information... but order is needed, and probably they should format this information in a better way.

    Because sometimes happen things like this question unanswered:

    http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/112/p/260118/1000265.aspx

    I am talking iabout something like FORUMS+WIKI+HOT STUFF, and some people working full time in them so info is updated daily.

  • 0 in reply to PAk
    Guru 117855 points

    PAk SY said:

    I am not afraid of sharing at all .... in fact:

    Let the record show - 24 days passed while you report being, "unafraid."

  • 0 in reply to PAk
    Guru 92251 points

    PAk SY said:
    Because sometimes happen things like this question unanswered:

    http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/112/p/260118/1000265.aspx

    i agree that sometimes formum questions go unaswered (has also happened to me).

    Have you tried the email or phone support contact options listed Contact Us?

  • 0 in reply to Chester Gillon
    Mastermind 7025 points

    Chester Gillon said:

    i agree that sometimes formum questions go unaswered (has also happened to me).

    Have you tried the email or phone support contact options listed Contact Us?

    Answer from the TI via Contact us:

    Dear XXXXX

    Thank you for contacting Texas Instruments. 

     

    In order to resolve your inquiry, we would kindly advise you to contact one of our official distributors who have their own support portal into Texas Instruments.

     

    Alternatively, we would advise you to utilize the knowledge and experience available on our e2e forum.  Our e2e community is constantly reviewed and managed by TI specialists according to product and is further supported by over 50,000 engineers from around the world sharing their knowledge and experience.  If you are already a member of our e2e community, you can post your question directly on our e2e community.

     

    If you are not yet a member of our e2e community, please click here and follow the instructions to become a member.

     

    For additional online assistance, please visit our Technical Support KnowledgeBase homepage at: http://support.ti.com/sc/knowledgebase 

    Kind Regards,

    ASKTEXAS Team
    Texas Instruments
    www.ti.com/asktexas

    Dead End or Infinite loop??