Interacting with software drivers with generated code

Hello,

I am using the simulink code generator and incorporating this code to a target.

Suppose that I have some functions on my target that allows me to turn on/off some LEDs, reading from an SD, etc. like:

led_on(6) -it turns on the led number 6

led_off(6) -it turns off the led number 6.

value = read_sd(30) -reads the parameter 30 on the sd card.

Now, what I want is to execute this function from the code generated directly. The ideal situation would be to write inside a MATLAB function in Simulink the piece of code I want to execute, but as expected, matlab does not understand the function led_on since it has not been declared previosly and of course, during the simulation I am not interested in running this function, only when running on a target.

Which could be the best possibily to achieve this? Of course I could set an output of the Simulink model and then setting on/off the led depending this output.

Thank you very much.