Hi constantinrazvan.chivu,
I appreciate your model and help, unfortunately I could not get it working still only using C code. The following is the SPI timing specs;

And in C the configuration that worked was as follows (it was tested with both 8 and 16 bits);

In Simulink I have it set up as follows with the memory block using uint8(2);

I believe these should be correct, I have tried various different configurations with the test file to get this to work on simulink with no luck.
Please let me know if you have any other suggestions.
Thank you,
Fernando