void EXTI0_IRQHandler(void)
{
if (EXTI_GetITStatus(EXTI_Line0) == RESET)
return;
DebounceDelay();
if (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_0) == 0)
return;
HandleUserButton();
EXTI_ClearITPendingBit(EXTI_Line0);
}
int main(void)
{
// ****************************************************************************** //
int state=0;
// TODO: Configure AD1PCFG register for configuring input pins between analog input
// and digital IO.
AD1PCFGbits.PCFG0 = 1;
AD1PCFGbits.PCFG1 = 1;
// TODO: Configure TRIS register bits for Right and Left LED outputs.
TRISAbits.TRISA0 = 0;
TRISAbits.TRISA1 =0;
// TODO: Configure LAT register bits to initialize Right LED to on.
LATAbits.LATA0 = 1;
LATAbits.LATA1 = 0;
// TODO: Configure ODC register bits to use open drain configuration for Right
// and Left LED output.
ODCAbits.ODA0 = 1;
ODCAbits.ODA1 = 1;
// TODO: Configure TRIS register bits for swtich input.
TRISBbits.TRISB2 = 1;
// TODO: Configure CNPU register bits to enable internal pullup resistor for switch
// input.
CNPU1bits.CN6PUE = 0;
CNEN1bits.CN6IE = 1;
// TODO: Setup Timer 1 to use internal clock (Fosc/2).
// Set Timer 1's period value regsiter to value for 5ms. Please note
// T1CON's register settings below (internal Fosc/2 and 1:256 prescalar).
//
// Fosc = XTFREQ * PLLMODE
// = 7372800 * 4
// = 29491200
//
// Fosc/2 = 29491200 / 2
// = 14745600
//
// Timer 1 Freq = (Fosc/2) / Prescaler
// = 14745600 / 256
// = 57600
//
// PR1 = 250 ms / (1 / (T1 Freq))
// = 250e-3 / (1 / 57600)
// = 250e-3 * 57600
// = 14400
// TODO: Setup Timer 1's prescaler to 1:256.
// TODO: Set Timer 1 to be initially off.
T1CON = 0x0030;
// TODO: Clear Timer 1 value and reset interrupt flag
TMR1 = 0;
IFS0bits.T1IF = 0;
// TODO: Set Timer 1's period value register to value for 5 ms.
PR1 = 575;
while(1)
{
if(IEC0bits.T1IE == 1) {
// TODO: For each distinct button press, alternate which
// LED is illuminated (on).
switch(state){
case(0):
DebounceDelay();
LATAbits.LATA0 = 1;
LATAbits.LATA1 = 0;
if(PORTBbits.RB2 == 0){
state = 1;
}
break;
case(1):
DebounceDelay();
if(PORTBbits.RB2 == 1){
LATAbits.LATA0 = 0;
LATAbits.LATA1 = 1;
if(PORTBbits.RB2 == 0){
state = 0;
}
}
break;
}
}
// TODO: Use DebounceDelay() function to debounce button press
// and button release in software.
}
return 0;
}