Arduino Due Simulation time with S-function block

Hi,

I built a DAC S-Function (DAC0 of the Arduino Due) block in Simulink.

Now my problem ist, that the simulation time in "External Mode" is very slow. If i try to send a sin with 50Hz i only get a sin with ~10Hz(running in "External Mode").

Is there any way to fix this?

(Matlab 2014a & Arduino Due)

Thank you in advance for your reply

[alexander sanchez]

can you show me how you did that, i`m trying to use my dac from arduino due in simulink i need it for a proyect