delay function working using for loop

[internetuser2k13]

hello,
i want to know the basic understanding of delay function, how its working.

void delay_sec(unsigned char seconds)    // This function provides delay in terms of seconds
{
    unsigned char i,j;

    for(i=0;i<seconds;i++)
        for(j=0;j<100;j++)
            __delay_ms(10);
}

 

[horace1]

__delay_ms(10);

delays fot 10mSeconds (1/100 of a second)

for(j=0;j<100;j++)
            __delay_ms(10);

delays fot 1 second , i.e. loops 100 times each delay 10mSec

 for(i=0;i<seconds;i++)
        for(j=0;j<100;j++)
            __delay_ms(10);

delays for a specified number of seconds

this type of delay means you cannot do anything else in the main control loop (interrupts can do other things but may upset the delay timing)

in practice one would probably use a timing loop driven by interrupts which allowed other things to happen

 

[mdvrajkot]

Hello internetuser2k13,

1.

        for(j=0;j<100;j++)
            __delay_ms(10);

Assuming that __delay_ms(10) functions generates the delay of 10ms.

total_delay_1 = 10ms x 100 = 1000 ms = 1sec

2.

     for(i=0;i<seconds;i++)
        for(j=0;j<100;j++)
            __delay_ms(10);

total_delay = 1 sec x seconds(variable)

3. It will generate the delay of approx. total_delay. Again for the accurate delay measurement we need to calculate the delay for the for loop and the variable declarations.