interrupt the led sequence WHEN RD6 is pressed on Explorer 16

Question

interrupt the led sequence WHEN RD6 is pressed on Explorer 16

unsigned int count1 = 500;
unsigned int count2 = 500;
unsigned int timerValue = 0;

int main(void){
TRISA = 0x00; // Set PORTA as output
TRISDbits.TRISD6 = 1; // Set SW3 input

int i;
int j;

while(1) {
// Toggle RUN LED (D10) every 3.5 seconds using Timer1
LATDbits.LATD0 = !LATDbits.LATD0;
delayFunc();

// Knight Rider pattern from Left to Right direction
for(i = 0; i <= 6; i++) {
LATA = (1 << i);
delayFunc();
}

// Knight Rider pattern: Left to Right or Right to Left depending on SW3 state
if (PORTDbits.RD6 == 0) {
for(j = 6; j >= 0; j--) {
LATA = (1 << j);
delayFunc();
}
} else {
for( j = 0; j <= 7; j++) {
LATA = (1 << j);
delayFunc();
}
}
}

return -1;

}

void delayFunc(void)
{
int j,k;
int a;

for(j = 0; j < count1; j++)
{
for(k=0; k < count2; k++)
{
a = 0;
}
}
}

Answer 1

To interrupt the LED sequence when RD6 is pressed on the Explorer 16, you can use the interrupt feature of the microcontroller. Here's how you can modify the code to achieve this:

1. Declare a flag variable to indicate if the LED sequence should be interrupted:
```c
#include <xc.h>
#pragma config FWDTEN = OFF

unsigned int count1 = 500;
unsigned int count2 = 500;
unsigned int timerValue = 0;
volatile int interruptFlag = 0;

void __attribute__((interrupt, no_auto_psv)) _INT0Interrupt(void)
{
interruptFlag = 1; // Set the interrupt flag
_INT0IF = 0; // Clear the interrupt flag
}

int main(void)
{
TRISA = 0x00; // Set PORTA as output
TRISDbits.TRISD6 = 1; // Set SW3 input

int i;
int j;

// Configure RD6 as interrupt pin
INTCON2bits.INT0EP = 0; // Interrupt on falling edge
IPC0bits.INT0IP = 2; // Set the interrupt priority to 2
IFS0bits.INT0IF = 0; // Clear the interrupt flag
IEC0bits.INT0IE = 1; // Enable the interrupt

while (1)
{
// Toggle RUN LED (D10) every 3.5 seconds using Timer1
LATDbits.LATD0 = !LATDbits.LATD0;
delayFunc();

if (interruptFlag == 0)
{
// Knight Rider pattern from Left to Right direction
for (i = 0; i <= 6; i++)
{
LATA = (1 << i);
delayFunc();
}

// Knight Rider pattern: Left to Right or Right to Left depending on SW3 state
if (PORTDbits.RD6 == 0)
{
for (j = 6; j >= 0; j--)
{
LATA = (1 << j);
delayFunc();
}
}
else
{
for (j = 0; j <= 7; j++)
{
LATA = (1 << j);
delayFunc();
}
}
}
else
{
// Do something else when interrupt occurs
// You can add your own code here
}

interruptFlag = 0; // Reset the interrupt flag
}

return -1;
}

void delayFunc(void)
{
int j, k;
int a;

for (j = 0; j < count1; j++)
{
for (k = 0; k < count2; k++)
{
a = 0;
}
}
}
```

In the modified code, we have added the interrupt handling routine `__attribute__((interrupt, no_auto_psv)) _INT0Interrupt(void)` to handle the RD6 interrupt. Inside this routine, we set the interrupt flag `interruptFlag = 1` and clear the interrupt flag `_INT0IF = 0`.

In the main loop, we check the interrupt flag `interruptFlag` before executing the LED sequence. If the interrupt flag is set, we skip the LED sequence and do something else.

Don't forget to configure the microcontroller for the correct behavior of the interrupt pin. In this example, we have set the interrupt to trigger on the falling edge `INTCON2bits.INT0EP = 0`. You may need to modify this depending on your specific requirements.