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MSP430FR5869: How many impedance of the GPIO P1.3 w/o and w/ interrupt enable?

Part Number: MSP430FR5869

Hi Sir,

How many impedance we would see for P1.3 pin when P1REN |= BIT3 ?

And how many impedance we would see for P1.3 pin if set input type(pull down) with interrupt enable?  Is Hi-Z status?

Below is the P1.3 register setting:

P1DIR  &= ~BIT3;        // Set GPIO P1.3 input
P1REN  |=   BIT3;        // Set Pull-up mode for P1.3
P1IES  &= ~BIT3;        // Rising edge interrupt
P1IFG  &= ~BIT3;        // Clear P1.3 interrupt flag
P1IE     |=    BIT3;        // Enable interrupt

P1SEL0 = P1SEL1 = 0;

Thanks.

Regards,

Sam

  • Hi Sam,

    The internal pull up/down resistors on the GPIOs have a typical value of 35k.

    When the pulldown resistor is enabled, the input impedance should be about 35k. Having the interrupt enabled or disabled will not change the input impedance. 

    A quick note - your comment in your code says "set pull-up mode for P1.3". What you are actually doing in that line is enabling the option for a pullup or pulldown resistor. In order to actually enable the pullup or pulldown, you need to use the PxOUT register. Please see below.

    Thanks,

    Mitch

  • Dear Mitch,

    Thank you very much for your kindly reply.

    Sam

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