Blink LED-while loop

Question

I'm trying to Blink and LED while Im holding a switch on the board, my initial code for blinking when the switch is on works fine. but now I'm trying to blink it while I'm holding the switch here is what I have for code, Can any one help point out where my error is, Thanks

#include <project.h>

int main()

{

uint8 SW_Stat;

for(;;)

{

SW_Stat=(SW1_Read());

while(SW_Stat==1)

LED_Write(1);

CyDelay(500);

LED_Write(0);

CyDelay(350);

LED_Write(1);

CyDelay(260);

return 0;

}

johnbeetem · Accepted Answer

There are several problems.

First, the C compiler doesn't care about indentation. It only cares about braces. So your code:

while(SW_Stat==1)

LED_Write(1);

CyDelay(500);

LED_Write(0);

CyDelay(350);

LED_Write(1);

CyDelay(260);

is going to be interpreted as:

while (SW_Stat==1) {LED_Write(1);}

CyDelay(500);

LED_Write(0);

CyDelay(350);

LED_Write(1);

CyDelay(260);

That is, the body of the while loop is the single statement LED_Write(1).

The second problem is that LED_Write(1) doesn't affect SW_Stat, so once SW_Stat == 1, the while loop will never end and the LED will be stuck on.

The third problem is that "return 0" exits main(), ending execution. Usually embedded programs are infinite loops and execute until someone powers off the device or hits the reset button. So you don't usually return from main().

jw0752 · Answer

Hi Jad,

I am not real familiar with this particular language but it looks like you may want to turn off the LED before you leave the while loop. Then you will always start with it off instead of on.

John