At some point I realised that abstracting to the level of "source_frequency" and "out_frequency" is too fragile, That will be going away in some places, will be

At some point I realised that abstracting to the level of "source_frequency" and "out_frequency" is too fragile, That will be going away in some places, will be added in another, where applicable. You are going to specify the exact PLL configuration, but zinc will compute the clocks for e.g. timer or UART based on frequency or baud rate.