MSP432,通过中断读取按钮二（J4.33）对应的GPIO引脚号码为P3.5的引脚状态： Add to module buttons a function called uint8_t check_and_clear_bb_flag (void). This function must carry out the following operations: save in a variable the state of bit 5 from Interrupt Enable SFR ...-Go服务器开发

Based on the given instructions, here’s an example implementation for the check_and_clear_bb_flag function in the context of MSP432:

#include <msp432.h>

static uint8_t button_bottom_flag = 0;

uint8_t check_and_clear_bb_flag(void) {
    // Save the state of bit 5 from Interrupt Enable SFR of Port 3
    uint8_t interrupt_state = P3IE & BIT5;
    
    // Disable the interrupt for pin 5 by clearing the bit
    P3IE &= ~BIT5;
    
    // Copy and clear the value of button_bottom_flag
    uint8_t local_button_bottom_flag = button_bottom_flag;
    button_bottom_flag = 0;
    
    // Restore (not just set) the enable interrupt bit for pin 5 of Port 3
    P3IE |= interrupt_state;
    
    return local_button_bottom_flag;
}

In this code snippet, we declare button_bottom_flag as a static variable within the module, which makes it local to the module and maintains its value between function calls.

The check_and_clear_bb_flag function follows the provided operations. It saves and disables interrupts using bitwise operations on Port 3’s Interrupt Enable SFR (P3IE). It then copies and clears button_bottom_flag, ensuring an atomic operation by disabling interrupts during this critical section. Finally, it restores the interrupt enable state and returns the copied value.

To use this function in your main function or any other part of your code, you can simply call check_and_clear_bb_flag(). This will give you a copy of button_bottom_flag while also clearing it.

Remember to adjust other parts of your code that previously accessed button_bottom_flag to use this new function instead.

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