At 12:06 PM 12/18/05 +0000, dennis_arm wrote: >Thank u Richard, > >I hope this works for me. > >but i am still left with my questions >about the overhead due to the inlization and comparing .. >in while and for loops.. > can u say something on this pls? Take a look at http://www.aeolusdevelopment.com/AppNotes/LPC210X/an-timerperformance.pdf I did exactly that kind of measurement for the timer set up in newlib-lpc. Feel free to take a look at that code for some thoughts on how to approach it. The code is also free for the taking ;) Robert " 'Freedom' has no meaning of itself. There are always restrictions, be they legal, genetic, or physical. If you don't believe me, try to chew a radio signal. " -- Kelvin Throop, III http://www.aeolusdevelopment.com/

An Engineer's Guide to the LPC2100 Series

The overhead is very compiler dependant and the best way is to take a look at the list file generated by the compiler. Your simple loop may also be longer if there are any interrupts during the loop execution. Richard. dennis_arm wrote: > Thank u Richard, > > I hope this works for me. > > but i am still left with my questions > about the overhead due to the inlization and comparing .. > in while and for loops.. > can u say something on this pls? > > regards, > dennis > --- In lpc2000@lpc2..., Richard Duits <yahoo@r...> wrote: > > > > Hi Dennis, > > > > I usually write short delays like this: > > > > void delay(unsigned int ticks) > > { > > unsigned int start = Timer0_TC; > > while (Timer0_TC - start < ticks) { } > > } > > > > > > This does not use any match registers, you only need a timer that > does > > not reset its counter. > > > > Regards, > > Richard. > > > > > > dennis_arm wrote: > > > > > Hi All !! > > > I am new to LPC2294 and wish to produce a small code for delay > some > > > thing like > > > > > > void delay (unsigned int Usec) > > > { > > > unsigned int delayUsec= ( ?? ) * Usec; // line 1 > > > volatile unsigned int count = 0; // line 2 > > > for (count = 0; count < delayUsec; count++) //line 3 > > > {asm volatile ("nop");} // line 4 > > > } > > > where time is the no of micro seconds > > > for information I am using a 60MHz crystal on my board > > > > > > I know it is easy to do with timers 0 and 1 but i wish, NOT to use > > > the timers at all as i need them for orther purpose. > > > My question > > > 1. is that is there any overhead added due to the code in the > > > function for the lines 1,2,3,4 ? > > > 2. is there any over head due to this "delay(/*some value*/)" > being > > > called in my over all code.? > > > > > > If so how much delay? or where can i get the > information? > > > > > > Am i missing some thing or is there a simple way to do this (to > > > caliculate the delay with out using tmmers?) > > > > > > > > > thanks in advance!! > > > > > > regards, > > > dennis. > > > > > > > > > > >. > >

Thank u Richard, I hope this works for me. but i am still left with my questions about the overhead due to the inlization and comparing .. in while and for loops.. can u say something on this pls? regards, dennis --- In lpc2000@lpc2..., Richard Duits <yahoo@r...> wrote: > > Hi Dennis, > > I usually write short delays like this: > > void delay(unsigned int ticks) > { > unsigned int start = Timer0_TC; > while (Timer0_TC - start < ticks) { } > } > This does not use any match registers, you only need a timer that does > not reset its counter. > > Regards, > Richard. > dennis_arm wrote: > > > Hi All !! > > I am new to LPC2294 and wish to produce a small code for delay some > > thing like > > > > void delay (unsigned int Usec) > > { > > unsigned int delayUsec= ( ?? ) * Usec; // line 1 > > volatile unsigned int count = 0; // line 2 > > for (count = 0; count < delayUsec; count++) //line 3 > > {asm volatile ("nop");} // line 4 > > } > > where time is the no of micro seconds > > for information I am using a 60MHz crystal on my board > > > > I know it is easy to do with timers 0 and 1 but i wish, NOT to use > > the timers at all as i need them for orther purpose. > > My question > > 1. is that is there any overhead added due to the code in the > > function for the lines 1,2,3,4 ? > > 2. is there any over head due to this "delay(/*some value*/)" being > > called in my over all code.? > > > > If so how much delay? or where can i get the information? > > > > Am i missing some thing or is there a simple way to do this (to > > caliculate the delay with out using tmmers?) > > > > > > thanks in advance!! > > > > regards, > > dennis. > > > > > >

Hi Dennis, I usually write short delays like this: void delay(unsigned int ticks) { unsigned int start = Timer0_TC; while (Timer0_TC - start < ticks) { } } This does not use any match registers, you only need a timer that does not reset its counter. Regards, Richard. dennis_arm wrote: > Hi All !! > I am new to LPC2294 and wish to produce a small code for delay some > thing like > > void delay (unsigned int Usec) > { > unsigned int delayUsec= ( ?? ) * Usec; // line 1 > volatile unsigned int count = 0; // line 2 > for (count = 0; count < delayUsec; count++) //line 3 > {asm volatile ("nop");} // line 4 > } > where time is the no of micro seconds > for information I am using a 60MHz crystal on my board > > I know it is easy to do with timers 0 and 1 but i wish, NOT to use > the timers at all as i need them for orther purpose. > My question > 1. is that is there any overhead added due to the code in the > function for the lines 1,2,3,4 ? > 2. is there any over head due to this "delay(/*some value*/)" being > called in my over all code.? > > If so how much delay? or where can i get the information? > > Am i missing some thing or is there a simple way to do this (to > caliculate the delay with out using tmmers?) > thanks in advance!! > > regards, > dennis. > > >. > >

Hi All !! I am new to LPC2294 and wish to produce a small code for delay some thing like void delay (unsigned int Usec) { unsigned int delayUsec= ( ?? ) * Usec; // line 1 volatile unsigned int count = 0; // line 2 for (count = 0; count < delayUsec; count++) //line 3 {asm volatile ("nop");} // line 4 } where time is the no of micro seconds for information I am using a 60MHz crystal on my board I know it is easy to do with timers 0 and 1 but i wish, NOT to use the timers at all as i need them for orther purpose. My question 1. is that is there any overhead added due to the code in the function for the lines 1,2,3,4 ? 2. is there any over head due to this "delay(/*some value*/)" being called in my over all code.? If so how much delay? or where can i get the information? Am i missing some thing or is there a simple way to do this (to caliculate the delay with out using tmmers?) thanks in advance!! regards, dennis.