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Compiler/EK-TM4C123GXL: Pin declaration PD0/PB6 are tied together?

Franklin ascarrunz
Prodigy 65 points
Part Number: EK-TM4C123GXL

Tool/software: TI C/C++ Compiler

Hi, 

I am using the EK-TM4C123G board and I would like to use the pins PD0,PD1,PB6,PB7 independently. These pins appear to be all tied together as in it is more like PD0/PB6 are one pin but have two different pins on the board and PD1/PB7 is the same way. Is there a way i can use all four pins as separate GPIO's? 

If i use some simple code in the infinite while loop with port D pin 0 declared as an output. (GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE,GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);) So the code below should just simply turn PD0 to 2.3V and then back to 0V(This was tested with a voltmeter). However the other pin PB6 also does the same. I would like to have these as separate pins. Any suggestions? 

GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_0,0);

SysCtlDelay(7000000);

GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_0,1);

SysCtlDelay(7000000);

  • 0
    Guru 117855 points

    Indeed!    You are (yet another) user to observe vendor's (less than stellar) decision to "marry" those 2 pairs of GPIO.

    You may "break" that (unwise) connection by "lifting" both R9 & R10.     We prefer to "tombstone each" (tack solder to one pad - w/part vertical) which is easily recognizable - and serves to alert "new board users" to the "presence of the fix."    

    We were (briefly/once) told that this "dead short" between MCU GPIOs was implemented to enable "consistency" w/older/lesser/Non-ARM MCUs.     (my suggestion - provide those "Plague-istors" in a small plastic bag - to be (only) installed by those seeking such (past) compatibility (5% of users - likely less) was rejected as "too hard!")         (yet endless user pain/suffering - never (appears) as too hard!)

    You are caught by vendor's "second unwanted decision" (force PD0 into an "unwanted" unlocking routine - to be "re-purposed" - to your choice.)    Your use of the Search Box - atop the forum - after entering keywords, "PDO - Unlock" - should guide, instruct and (then) yield the results you seek.

    Vendor has "forever" known of the "resistance" to these 2 decisions - yet (any) fix is "too hard" - and posters' (continue) to expend time/energy - endlessly falling victim...    (such "victimization" - not judged, "hard!")

  • 0
    TI__Guru**** 184486 points

    Hi Franklin,

     As suggested by cb1, you will need to break R9 and R10 on the LP board. 

  • 0 in reply to Charles Tsai
    Guru 117855 points
    Better yet - "shoot" those who "voted" for "past compatibility" at the sacrifice of, CURRENT USER SUCCESS/COMFORT!
    Compatibility appears (much) "in the noise" - yet posters "Fall from this high cliff" - many times each/every week...