@classmethod
def get_pll_mhz(mcs, pll_reg):
    """The getter method for PLL output clocks.

        Parameters
        ----------
        pll_reg : Register
            The control register for a PLL

        Returns
        -------
        float
            The PLL output clock rate measured in MHz.

        """
    pll_fbdiv = pll_reg[mcs.SRC_PLL_FBDIV_FIELD]
    clk_mhz = mcs.DEFAULT_SRC_CLK_MHZ * pll_fbdiv
    return round(clk_mhz, 6)
