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For the M051 series in the NuMicro® family, for example, the GP01_INT interrupt handler is shared by 16 pins of P0 [7: 0] and P1 [7: 0]. After an interrupt is triggered and the GP01_INT interrupt handler is entered, it is needed to determine a trigger source for the corresponding action.

Table 1 M051 Interrupt Mapping Table

When an interrupt is triggered, the interrupt flag of the corresponding pin will be set, and the interrupt flag in the ISRC register can be sequentially checked to determine the trigger source. Refer to the following example.

#define GPIO_GET_INT_FLAG(port, u32PinMask) ((port)->ISRC & (u32PinMask))

void GPIOP0P1_IRQHandler(void)
{
if(GPIO_GET_INT_FLAG(P1, BIT3))
{
//To check if P1.3 interrupt occurred
GPIO_CLR_INT_FLAG(P1, BIT3);
//do something…
}
else if(GPIO_GET_INT_FLAG(P1, BIT4))
{
//To check if P1.4 interrupt occurred
GPIO_CLR_INT_FLAG(P1, BIT4);
//do something…
}
else if(GPIO_GET_INT_FLAG(P1, BIT5))
{
//To check if P1.5 interrupt occurred
GPIO_CLR_INT_FLAG(P1, BIT5);
//do something…
}
}