Hi folks i am trying to generate a square wave of frequency 256KHz but iam not able to; maximum i am able generate upto 65KHZ
this is the code ia m using
int out = 9;
void setup() {
pinMode(out, OUTPUT);
}
void loop() {
int state = 0;
while(1)
{
if(state == 0)
{
digitalWrite(out, LOW); state = 1; }
else
{ digitalWrite(out, HIGH); state = 0; }
delayMicroseconds(1);
}
}
If you're trying to do something fast, it's best to keep your code simple.
That is not the way to generate a fast square wave. The micro seconds delay has a resolution of 4 microseconds and digitalWrite takes too long.
Assuming you don't want to do anything else then change them to the direct port access equivlent instructions.
thanks grumpy_mike can u help me with the instructions i am not used to it
See
Thanks mike 
You could generate 253.97 or 258.06kHz by programming one of the timers
to count at full rate and wrap every 63 or 62 clock cycles (for a 16MHz system clock).
Arduino Due (<13$) can generate much higher frequencies.
DueVGA library generates more than 30MHz for 960x720 monochrome display @47Hz
(not counting invisible pixels outside 960x720 area: 96072047/1024/1024=30.98):
Hermann.
Thanks MarkT can u please help me in coding timers i'm not used to it
What exactly do you want to do? Generate a fixed frequency or a variable one? And why?
Hint - other people have done this, there is a search facility, you might find good examples if you look
