Hi all,

I modified my code as u suggested, and still wrong, the thing is: The first round I burnt the code into the uC, it works, I can see the sent signal from MATLAB to uC, and then I reset my uC and sent the same signal from MATLAB to my uC, and no more reaction....From now on the uC stopped working at all. I tried like replugging the power, etc...I'm not sure if it was because some pin was locked or only in the first round the uC and MATLAB can synchronize to the same baud rate, then no more.

I use a USB development board from http://www.futurlec.com/USBDevBoard.shtml. There's already a MAX232 on the board. The uC is to control a demultiplexer, through which a signal can be demultiplexed to different channel, the output of the signal to which channel is defined by the MATLAB order, therefore I need the serial communication. Only the first time the input signal can be sent to my expected channel, so I'm thinking could it because that after the first time demultiplexing the demux has been locked?