This Simulink model shows a simple code to convert decimal to binary numbers up to 8 bits (0 to 255 dec). It is easily configurable however, e.g if 9 bits is required, simply change 2 lines of the codes int he Matlab function block as shown below:
1)
a=zeros(1,8);
to
a=zeros(1,9);

2)
x=[a(8),a(7),a(6),a(5),a(4),a(3),a(2),a(1)];
to
x=[a(9),a(8),a(7),a(6),a(5),a(4),a(3),a(2),a(1)];

The code was modified to remove the bug during conversion at decimal 0.