use of UARTs in the background

atekippe

Does anybody know where I can get some more information on using the buffered serial communication in the background?· I know how to·set up the Uarts and use them in the main program to communicate with each other but am I missing something about the background that could speed up my program?

atekippe
ISU

atekippe

Also, during our continuous comminication with the device we get this error.

[noparse][[/noparse]Error IDE-0028] Unhandled exception in JVM:java.lang.OutOfMemoryError.
Exception thrown in file 'C:\Program Files Inc.\Javelin Stamp IDE\lib\lang\StringBuffer.java' at line 272

Is there a way to clear the memory so it never reaches it's upper limit or another way to get around this?

Here is the code we are running

//

---

Routine to receive entire responce in buffer

---

static void bufferMessage(){
c = 0xff;
count = 0;
while (count <1){
//if(rxUart.byteAvailable()){
c = (char)rxUart.receiveByte();
if(c=='\n'){
count=1;
}
buffer.append(c);

}
}


//

---

Main Program

---

public static void main(){

while (count < 101) {
buffer.clear(); // clear buffer

//

---

Uart commands poling epoch4 for Peak Thickness

---

txUart.sendString("PH? \r\n"); // ask for peak thickness

bufferMessage(); // call receive subroutine

if (count>99){
System.out.println(count);
System.out.println("out of loop");
}

else {

x=buffer.length();
count=0;
while (count <x){
l=(char)buffer.charAt(count);
if(l==m){
u=count;
}
if(l==n){
v=count;
}
count=count+1;
}
if (x>1){
buffer.delete(u-1,x); // deletes from buffer 6 to end of string
buffer.delete(0,v+4); // deletes front 3 chars in buffer
// System.out.println("

---

Peak Thickness [noparse][[/noparse]in]

---

");
String s = buffer.toString(); // prints to screen remaining chars
System.out.println(s);
}
}

atekippe
ISU

Peter Verkaik

If you look at the StringBuffer class, you'll see that

append() calls expand() that creates a new string if the

buffer is too small. And because there is no garbage collection

you eventuelly run out of memory.

You can better use a simple char array plus index pointer to

store c. This minimizes code and speeds up your application.

static char[noparse]/noparse buffer = new char[noparse][[/noparse]100];

static int index=0;

static void readMessage() {

· int c;

· index=0; //start new message

· while (true) {

··· while (!rx.byteAvailable()) ; //wait for input

··· buffer[noparse][[/noparse]index++] = (char)(c = rx.reaceiveByte());

··· if ((c == '\n') || (index>=100)) return;

· }

}

regards peter

atekippe

Thanks peter,

atekippe
ISU