S32K324 ADC resolution bit

[jack_22]

Hello, I would like to ask a question. I am using a chip, S32K324, and the AD written on the chip is 12 bits. However, in the manual, the CALLISTREG register can select 4 different bits, 14 bit, 12 bit, 10 bit, and 8 bit. How do I understand this? Isn't the conversion result always 12 bits? How many bits for S channel, P channel, and X channel, respectively? Thank you!

[Robin_Shen]

Hi

The 12-bit resolution is officially supported, there are specs in the Data Sheet based on that.

Conversion data is always 15bits wide, regardless of the conversion resolution selected (14, 12, 10, 8 significant bits per conversion data, reducing this number speeds up the conversion because the SAR algorithm executes fewer steps).

How many bits for S channel, P channel, and X channel, respectively? The resolutions of the three types of ADC channels are the same. Due to the difference between Pin capacitance, Analog Bus Capacitance, and Channel selection Switch impedance, Precision channel is more accurate.

Best Regards,
Robin
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[ustaufuk]

"The 12-bit resolution is officially supported"

What do you mean officially supported? It is really confusing that datasheet says 12-bit. Is there any kind of scaling on HW layer?

[Robin_Shen]

Selectable resolution (8-, 10-, 12-, 14-bit).
However, please note that the TUE spec for precision and standard channels is based on 12-bit level resolution.