S32K1 - Using analog pin in ADC and CMP simultaneously?

[Joey_van_Hummel]

Hi all,

Quick question. I've searched the S32K-DS and S32K-RM documents as well as AN12217 and series cookbook for answers, but couldn't find out. Hoping you can tell me;

If I have a signal connected to e.g. ADC0_SE0/CMP0_IN0, what happens if both peripherals (ADC and CMP) try to sample this signal? Can both peripherals sample this signal simultaneously? Will there be any consequences to doing this, how is muxing between these peripherals implemented?

Kind regards,

Joey

[PetrS · Accepted solution]

Hi,

technically, yes - since each module has its own mux and input stage, they can operate in parallel. However, if the analog signal is shared, the loading effects (e.g. input impedance, capacitance) could affect accuracy.  If both modules try to sample at the same time, you might get inaccurate ADC readings or unstable comparator behavior. The analog mux and sampling circuitry might load the signal differently depending on which module is active.
So a best practices should be avoid simultaneous use of the same pin for both ADC and CMP unless absolutely necessary.

BR, Petr

[Joey_van_Hummel]

Hi @PetrS 

Thank you for your quick and detailed reply. I will take this into consideration for our design.

Kind regards,

Joey