Posted on June 07, 2016 at 20:46Hi to all,
I got a problem with GPIO interrupt.
I have two buttons connected to pin 13 and 14 of port A.
I configured pins in input and enabled interrupt, then I wrote the interrupt routine.
When I pushed a button I got an interrupt, but I am not able to determine which button is pressed.
EXTI->PR gives always 0x6000
GPIOA->IDR gives 0xF00 or 0xE00 for both buttons.
How can I distinguish the buttons?
Here is my code:
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#define BUT0 13 //GPIOA
#define BUT1 14 //GPIOA
MYBUTTON::MYBUTTON()
{
if(!(RCC->AHBENR & RCC_AHBENR_GPIOAEN)) RCC->AHBENR |= RCC_AHBENR_GPIOAEN; // Enable GPIOA clock
GPIOA->MODER &= ~(0x03U<<(2*BUT0) | 0x03U<<(2*BUT1)); //Mode function: 00=input; 01=output; 10=alternate; 11=analog
GPIOA->MODER |= 0x00<<(2*BUT0) | 0x00<<(2*BUT1);
GPIOA->OSPEEDR &= ~(0x03U<<(2*BUT0) | 0x03U<<(2*BUT1)); //Pin speed = low speed
GPIOA->OSPEEDR |= 0x00<<(2*BUT0) | 0x00<<(2*BUT1);
GPIOA->PUPDR &= ~(0x03U<<(2*BUT0) | 0x03U<<(2*BUT1)); //Pull up: 00=No pll up/down; 01=pull up; 10=pull down
GPIOA->PUPDR |= 0x01<<(2*BUT0) | 0x01<<(2*BUT1);
/* Interrupt configuration */
SYSCFG->EXTICR[3] |= 0x00000880; // Pin 13 and 14 of GPIOA
EXTI->IMR |= 1L<<BUT0 | 1L<<BUT1; // Interrupt MASK
EXTI->FTSR |= 1L<<BUT0 | 1L<<BUT1; // Falling trigger
}
and the interrup routine:
extern ''C'' void EXTI4_15_IRQHandler()
{
uint32_t a,b,c;
a=EXTI->PR;
b=EXTI->EMR;
c=GPIOA->IDR;
myusart1.PrintString((uint8_t *) ''BUTTON INTERRUPT'', ' ', 0);
myusart1.PrintHex(a, ' ');
myusart1.PrintHex(b, ' ');
myusart1.PrintHex(c, '\n');
EXTI->PR |= 1L<<BUT0 | 1L<<BUT1; // Reset interrupt status register
return;
}
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Thank you
Freya
