RTSLVU wrote:
Instead of hard wait times I suggest you use the "bytes at port" to wait just long enough to get the data.
My example shows waiting until the byte coult is not=0 but if you know the exact amount of bytes and it's always going to be the same change it to wait until you get that byte count.
You can adjust the loop delay if needed too.
Not a good idea.
Suppose your incoming message is expected to be 10 bytes. You wait unti the bytes at port != 0. Suppose only 1 byte as arrived at the instant you check that property node. Now the loop ends, you read only the 1 byte. The other 9 that make up the message get left hanging in the serial port and you return with an incomplete message.
I find that relying on bytes at port is very rarely the correct solution for a serial communication scheme.
You could wait for bytes at port not equal to zero. But don't use that number for the bytes to read. Use the expected number of bytes or a sufficiently large number of bytes and the termination character to end the read. But even if you do, you should probably still have a timeout mechanism in your waiting loop so you don't cause your program to freeze waiting for bytes that may never arrive due to some reason such as a disconnected serial cable.
Message Edited by Ravens Fan on 11-03-2009 01:46 PM
