Serial Port Timing Issues

I am trying to establish serial communications between an Arduino and a WIN10 machine. I am using the USB / FTDI arduino connection.

The arduino code is simple-it listens on the serial port, and when ANYthing arrives it simply sends out a phrase. I tested this on a windows serial terminal and it works fine--entering any character returns the phrase. I use the LED on the board to show that data arrived. (see attached zip)

Now, coding the Matlab side, it works sporadically. In the attached code and I show a work around--issue the character to the arduino twice, and wait 2 seconds in between sends. The LED lights both times. Waiting a smaller amout of time generally (but not aways) results in a "Not returned within Timeout" condiiton.

I am expecting that this is some type of timing problem-the MATLAB session is not "listening" in time. I did not see any timing settings in the serialport command. And trying to code a wait on NumBytesAvailable hung matlab as well.

Any ideas appreciated

Fritz

Answer 1

[Fritz Sonnichsen]

Here is a further clarification on this problem. In the attached code things run as expected--however-I must start with a pause(3) after issuing the serialport command. Apparently matab is slow here and needs time to finish the serial setup. I assume this is a bug-it should wait until it is ready. I do not see anything in the doc that has a wait after issuing the command.

Not pertinent here but worth mentioning: I also see an issue with the "terminator" command. The formalities of serial communications do not require a terminator and in fact in computer-to-computer communications this is often not wanted. However viewing other posts it seems as though matlab forces the terminator.

Fritz