Developing a driver to enter standby mode and wake up

Create a copy of your previous project in your IDE, following the steps outlined in earlier chapters. Rename this copied project StandByModeWithWakeupPin. Next, create a new file named standby_mode.c in the Src folder, and then another file named standby_mode.h in the Inc folder.

Populate your standby_mode.c file with the following code:

#include "standby_mode.h"
#define PWR_MODE_STANDBY        (PWR_CR_PDDS)
#define WK_PIN                (1U<<0)
static void set_power_mode(uint32_t pwr_mode);
void wakeup_pin_init(void)
{
    //Enable clock for GPIOA
    RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
    //Set PA0 as input pin
    GPIOA->MODER &= ~(1U<<0);
    GPIOA->MODER &= ~(1U...