fwrite to serial object works only in async mode

Hi all,

I am writing a script in Matlab to cummunicate through bluetooth. To do so, I have a usb to bluetooth module connected to my PC for which I create a COM port connection. The recieving end is a HC-05 bluetooth module.

I have previously managed to create the connection and send and recieve data using the fwrite/fread functions. Now I had the need to use the connection again but when I tried to use the same sceipt, a write error is displayed and the only way I managed to communicate is when I use the async mode. Strangly enough, when I dont use the async mode, and I get the write error, data is still transmitted and recieved by the recieving end.

Does anyone have any idea why this could happen?

Thanks