I am developing an embedded system based on AT91SAM9263-EK development kit. I have a communication controller which uses serial port to communicate with the development board. I built Windows CE 6.0 R3 with all the latest patches for Platform Builder. For development, I use Visual Studio 2008 with .NET compact 3.5 and C# language, together with SerialPort class to communicate to the device.
Communication problem works like this: I assert DTR signal of serial port, and the communication controller returns a status message. Then I return DTR signal to it's original value. The problem I am facing is following:
* I open serial port (COM2, baudrate 19200) and assert DTR. On the oscilloscope I can see that the controller correctly sends the data, but I do not receive any data. I can repeat this as many times as I want, but no data is received. When I close the port, all data which was sent is received at once. So, if I asserted the line 10 times, a receive 10 status messages when I close the port.