plot waveform by serial port with ARM

hi there
i programing a processor arm lpc1768 for A/D converter (8-bit) then send data by serial port (milivolt) and recive it by labview correctly but the problem is when i plot it to the wave chart (real time) the value that shown are discrete not continues! and because of that my output waveform is nothing but some peak!
can anyone here help me with that?
i attach my design and the result
thanks