Matlab serial communication help .converting vb.net syntax to matlab?????

so i'm taking data from atmega 644 serially into computer, the hardware's working fine and my vb.net program is sucessfully detecting and plotting the data as graph but now i want the same data in matlab.

the condition set for sending-receiving data is that the program burned in atmega sends two start bits 'x' and 'y' and the end program in vb.net receives it by asc('x') and asc('y') which enables serial communication between them. i want to know how can i perform the same task of receiving these two bits 'x' and 'y' in matlab serially from atmega 644 s= serial('COM1') i tried fscanf(s,'x'); and also str2double(freadf(s,'x')) which gave matching failed error saying formats are not matching. REST OF CODE IN MATLAB HAS NO COMPILING ERRORS