SAADC input range in differential mode

[NewtoM]

Hello,

just a quick question for my understanding: If I use differential mode and have the Vp and Vn pins as an input channel to the SAADC, then may I only supply Vp with positive and Vn with negative voltage, respectively?

Thanks,
Tamas

[Kenneth]

Hi,

Both Vp and Vn must be between GND and VDD, the difference is that Vn is not fixed to GND but can be between GND<Vn<Vp.

Best regards,
Kenneth

[NewtoM]

That is, Vp is my highest possible input value and Vn is the input to be measured, where Vn=Vp gives me the maximal (digital) AD value and Vn=0 gives me zero (at least in theory)?

[Kenneth]

You are measuring the difference between the two, so Vn=Vp should give 0.

Best regards,
Kenneth

[NewtoM]

Thank you very much!