Serial port receive buffer issue

Forum 2005-2010 (read only) Software Troubleshooting
1

Hi guys.

I'm working on an arduino mega and I'm trying to read the serial buffer after I filled it up from the serial Monitor.
I read that the buffer size is 128 bytes, but what I get from the serial.available() is just 49 characters. Anyone know why this is happening?

Thanks in advance.

2

Because you only sent 49 characters?

3

nope, they're almost a hundred.

this is the string I sent

TEM:20.5,HEA:50.7,TMS:17.5,TMN:18.5,LUM:700,LGH:1,NOI:755,FIN:1,HUM:50.4,CHS=1300\0

4

if (Serial.available() > 0)
{
int index=0;
delay(100); // let the buffer fill up
int numChar = Serial.available();
Serial.println(numChar);
}

this gives me back 49

5

What's the line speed?
Perhaps the sender only got through 49 in the 100ms allowed by your sketch.

6

Thank you AWOL you saved my life.

7

Using "delay" for one tenth of a second is a waste of processor power, and specifying delays like this depends on different factors.
Much better to monitor "available" until enough data has been received to proceed.

As a simple rule-of-thumb, at 9600 baud, one character takes a little over 1ms to transmit.