Why my uC receives values in the 65..127 range only(simulink model, RS232 communication)

Hi,

I want to send values to my PIC microcontroller via RS-232, but if i send something different than numbers in the 65..127 range, it gives me weird values. For example, Send 0, receive -192. send 65 receive 65

I'm using Matlab&Simulink R2009b, the serial setup is 9600 baud rate, little endian order, 8-bit, parity none. Using the 'Constant' block to send value(type of uint8, double, - tried them all)

What is the problem?

Thank you, Zoltan