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How to handle unused pins on DM365

Omin Chou
Genius 3555 points

Dear all,

I have some pins that do not use on DM365 as below list. Because those pins do not have internal pull down or high. Even if those pins are output pin, I still want to confirm this portion. Can anyone give me some advice to handle those unused pins? Thanks in advance.

B.R.

OC

  • 0
    Genius 3555 points

    Hi all,

    Can anyone give me some replies on above discussion? Thanks a lot.

    Another question, if the ADC is not used, the datasheet recommended to either leave open, as no connect, or tie along with the other ADC_CHs together to a single resistor to ground. Why those pins can be left open or connected a resistor to ground? Can TI provide a internal circuit to explain this portion? Thanks in advance.

    B.R.

    OC

  • 0 in reply to Omin Chou
    Intellectual 985 points

    OC,

    We tied all the ADC lines through a 2.2K resistor to gnd and it seems to be fine.  I haven't done anything to confirm it, but the device works. 

    For other unused I/O, I have similar questions.  But here are some guidelines:

    http://processors.wiki.ti.com/index.php/General_Guidelines_for_Reducing_I/O_Power_Consumption

    http://processors.wiki.ti.com/index.php/DM36x_Schematic_Review_Checklist  (look at the bottom where it says: For any unused pin you should pay attention to how it is terminated. Frequently pins will default to an input state and if they are left floating they may pick up noise and toggle at a high frequency. This can cause significant unwanted current consumption. Unused pins should be checked to see if they can be configured through software as outputs so they are not floating. If there is an internal pull-up/down you should configure the level of the output (high/low) to match the pull-up/down for lowest current consumption. )

    Hope this helps a little.  I will be watching this thread to see if TI responds.

    Thanks,

    David Havell