MSP430G2452: Reduce the current draw for an input interrupt

Part Number: MSP430G2452

Hi Team,

Our customer would like to know if there is a way to reduce the current draw for an input interrupt that is configured to trigger on a low to high [or high to low] transition in LPM3 mode and has its internal pull-up enabled?

Thank you for your support!

Regards,

Danilo

  • Most of the current draw is in the pullup, so use an external one or none at all.

  • What purpose is the pullup serving, i.e. what's at the other end of the wire? Two common cases:

    1) To keep a normally-floating circuit from floating (canonical push-button). The pin only draws current when the switch is closed. The REN resistor is already pretty weak (25-50k); if you weaken it further e.g. using an external 100k, it will be susceptible to EMI (aka "antenna").

    2) For a pin which is normally driven by the other end of the wire, but someone might 'forget" to plug it in. For this case it might suffice to do a probe at startup and, if it's evident the pin is connected to the other end, turn off the REN resistor.

  • Hi Keith and Bruce,

    Thank you very much for your responses.

    Regards,

    Danilo