I can test the filter using python and the Zynq board.

The CIC filter is described as:

$$ H(z) = \Bigg ( \frac{1-z^{-RM}}{1-z^{-1}} \Bigg )^N $$ Where R is the decimation rate, M is the number of samples pre stage(1 or 2), and N is the number of stages in the filter.

After the Z transform this operation is:

$$ y[n]=y[n-1]+x[n]-x[n-RM] $$

The order of the filter is how many filters are connected in cascade, that is the output of the filter is the input of the next one.

The CIC filter is composed by an integrator and a accumulator. The integrator is:

$$ Y[z] = \frac{1}{1 - z^{-1}} \quad \Rightarrow \quad y[n] = y[n-1] + x[n] $$

Where y is the output and x is the input.