I have a circuit with split ground planes one for analog, and one for microcontroller/DC-DC etc. The microcontroller will be using its ADC to sample from the analog circuitry.
Ideally I would like to connect the microcontroller to analog ground, so that the ADC voltage measurement is correctly referenced to the analog ground, and not digital ground. However, as the microcontroller is inherently noisy, this is likely to create return current thought the analog ground, which is not something I want. (Previous versions of the circuit have had significant problems with noise).
What is the best practise here?