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TCA8418: unused pins

Viggo Joergensen
Prodigy 160 points
Part Number: TCA8418

Hi,

according to datasheet revised June 2018 page 3 unused pins should be connected to Vcc via pull-up.

Isn't it possible to mask out rows and column pins used for the key matrix and forget about the rest?

This product is not battery powered, so no power concerns.

best regards

  • 0
    TI__Guru 73591 points

    Hey Viggo,

    The concern on unused pins should be connected to Vcc is because of shoot through currents which could occur if an input is left floating. This results in higher current consumption (Higher Icc) so if you are not battery powered then this is less of a concern. 

    On a side note, you can make the unused Rows/Columns enable their own pull up resistor. (Set unused to be GPIO mode and then set the GPIO_pull upx registers to be enabled)

    Thanks,

    -Bobby