• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 29 subscribers
  • Views 585 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.

TM4C123GH6PM - 2 GPIO pins always show 'LOW'

Theng Hoo Koay
Prodigy 160 points
Other Parts Discussed in Thread: TM4C123GH6PM

Hi there,

We are using TM4C123GH6PM in one of our project and currently we are facing a problem in below 2pins of the mcu.

 1. PE0 -- to control led 9

2. PD7 -- to control led 4

 

We connect those pin to a transistor to turn on the led. Actually we using about 9 led (led 1 ~ led 9) on this project, all the other pins have no problem and only this 2-pin having problem. We have tried to set all PE & PD port to output (High), but only PE0 and PD7 not working. The transistor and led are confirmed no problem. Please help to check why it can be happened. Any other special setting need to take care?

 Attached with the MCU and LED schematic for your reference.

Thanks for the prompt attention.

3288.led Schematic.pdf2656.MCU Schematic.pdf-Koay

  • 0
    Guru 117855 points

    Alas - yet one more, "victim" to PD7's default NMI behavior!

    Good read of gpio section - your MCU manual - will reveal that PF0 & PD7 require, "special treatment" prior to, "normal use."  You must first "unlock" that pin - then it should respond as your subsequent, "set-up/config" dictates.   Unlock procedure described in your MCU manual and w/in many, many posts - this forum.

    PE0 does not similarly, "compute" - by my memory.  Don't know your MCU - our 64 pin LX4F reveals PE0 as both ADC and UART capable - and should support GPIO as well.  Might there be some "extra" connection to PE0 - causing your plight?

    Also possible that your set-up/config of Port E "prevents" PE0 from behaving as a proper output - that is worth your review.  When all else fails - review of Port E's Registers should unlock  (bad word choice) remove any Port Pin mystery...