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Index › Programming Questions & Help › Electronics,  Serial Library › Sending Serial slows processing down
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Sending Serial slows processing down (Read 1179 times)
Florito
Sending Serial slows processing down
Oct 23rd, 2006, 2:57am  
Hi all,

I hooked up my Arduino board which controls 3 PWM pins to Processing. My processing sketch is running some fluid-like simulation (framerate is fine). This simulation returns 3 values, with which I want to control the 3 PWM values.
I am sending 6 bytes every loop on 115200baud to the Serial port. These 6 bytes alone already slow my processing sketch down severely. As I said, without the serial output, it runs smoothly.
Has this occured to others? Am I doing something wrong, or does the serial port have some kind of latency?
I am running processing on a PC and the Arduino board through USB.
Thanks for your help
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Florito
Re: Sending Serial slows processing down
Reply #1 - Oct 23rd, 2006, 3:24am  
(own-reply)

I think I already solved the problem.
the code looked like this:
Code:
for (int i=0;i<3;i++) {
  myPort.write(index[i]);
  myPort.write(value[i]);
}

Now instead of writing (int)egers I thought I'd give it a try in writing an array of bytes at one time
Code:
byte[] message = new byte[6]
for (int i=0;i<3;i++) {
  message[i*2]=(byte)index[i];
  message[i*2+1]=(byte)value[i];
}
write(message)

And now it works perfectly!
It looks like everytime you call a 'write' it first has to open the port or something like that...

Anyhow, I thought I'd share this, since some others might stumble upon the same problem.
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