$2.$

$(15$ points$)$

$3\mathrm{.}3$V

Use the circuit above to complete the program which starts below, and ends at the next page.

$```$

$//$ Mask for the external LED

#define MASKA

$```$

$//$ Mask for the external SWITCH

#define MASKB

$```$

int main $($void$)\{$

$//$ Clear the GPIO clock register

$```$

$//$ Enable the GRIO clock for the respective Port$($s$)$

$//$ Enable digital function at the GPIO ports for the

$//$ external switch and external LED

$//$ Set the direction $($input or output$)$ of the GPIO pin connected to

$//$ the inverter

$//$ Set the direction of the GPIO pin connected to the

external switch

$//$ Turn off the external LED

$//$ If the external switch is closed,

$//$ toggle the external LED;