help with a delay function - Electronic Circuits Projects Diagrams Free

t.man · 22nd May 2008, 08:55 AM

i want to make a delay of, say 100uS using 1 Mhz oscilator, so i see a function like this can do the work,

Code:

void delay(unsigned char i)
{
	unsigned char n;
	unsigned int j;
	for (n=1; n<i; n++)
	{
		for (j=1; j<1535; j++);
	}

...but my problem is how to figure out how this function really do the delay of, say 1 seconds, etc. when it is called.

anyone to come to my rescue?

thanks,

ericgibbs · 22nd May 2008, 09:10 AM

Quote:

Originally Posted by t.man

i want to make a delay of, say 100uS using 1 Mhz oscilator, so i see a function like this can do the work,

Code:

void delay(unsigned char i)
{
	unsigned char n;
	unsigned int j;
	for (n=1; n<i; n++)
	{
		for (j=1; j<1535; j++);
	}

...but my problem is how to figure out how this function really do the delay of, say 1 seconds, etc. when it is called.

anyone to come to my rescue?

thanks,

hi,
If you are using a PIC with a 1MHz crystal.? the internal cycle execution time will be 1MHz/4 ie: == 4uSec/execution cycle.

I dont program in 'C', but the idea is the same in assembler.
You count the total program execution cycles [bytes] around the loop, this gives the total delay period.

Do this help.?

Pommie · 22nd May 2008, 09:53 AM

You can run it in the simulator and use the stop watch to time it. Alternatively, you could include the delay routines supplied by Microchip.

Mike.

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22nd May 2008, 08:55 AM	(permalink)
t.man	help with a delay function i want to make a delay of, say 100uS using 1 Mhz oscilator, so i see a function like this can do the work, Code: void delay(unsigned char i) { unsigned char n; unsigned int j; for (n=1; n<i; n++) { for (j=1; j<1535; j++); } ...but my problem is how to figure out how this function really do the delay of, say 1 seconds, etc. when it is called. anyone to come to my rescue? thanks,

22nd May 2008, 09:53 AM	(permalink)
Pommie	You can run it in the simulator and use the stop watch to time it. Alternatively, you could include the delay routines supplied by Microchip. Mike.