How to determin a delay

[OutThere]

How would i determine how long it takes to complete an instruction?

for the below function i can pass an unsigned char "count" so i can adjust the delay ….so lets say I pass 1 how long would it take to complete both for loops especially the second where j exceeds 112 and exits the for loop ?

void delay(unsigned int count)  
{
 int i,j;
 for(i=0;i<count;i++)
 for(j=0;j<112;j++);
}

[hamster_nz]

In this case, delay will take no time at all - all good compilers will see that the code does nothing, and optimize it away. What platform are you targeting? If Linux, usleep() might be what you need.

Maybe if you added an (non-portable) inline assembly instruction to the loop you might get some form of delay. If you do want to count clock cycles to give short pauses you would most likely be better off coding the function in assembler.

When I have needed to time precise delays, I either call the function a million times, and time the overall program (e.g. so if it takes 10s to run, each call takes 10 microseconds), or if this is a microcontroller project I hook a logic analyzer to the hardware, and measure it that way.

[OutThere]

it's for an embedded microcontroller to interface w/ an LCD. When the LCD is powered on it takes 10ms to initialize where no instructions can be written. Durring this time the Line D7 is high then goes low after 10ms. So my choices are to either make a 10ms delay or read D7 for when it goes low.

[hamster_nz]

Does the environment you are using have a 'millis()' (or equivalent) function you can call, to monitor a timer?

millis() - Arduino Reference

   end_time = millis()+11;
   while(millis() != end_time) 
      ;  // do nothing

Or maybe better (due to timer rollover and the possibility of long interrupts)

   start_time = millis();
   while(millis() - start_time <= 10) 
      ;  // do nothing

[stahta01]

You should read up on the timer and delay support for your embedded hardware! This is one area that changes a lot from one hardware platform to another.

Tim S.