Looking at the datasheet for the ADC Delsig, it specifies that when input range is set to Vssa to Vdda, the ADC delsig behavior is ratiometric. Is this saying that that both Vref and input values of the ADC are being divided by 4, so the output equation for the ADC will be:
d = ((Vin/4) / Vref) x 2^n where d is the n-bit output of the ADC and Vref = Vdda / 4?
I would just like to get a definitive answer because it's not 100% clear to me from the delsig datasheet.
Yes, as you have pointed out, the measurement made is ratiometric. The reference value used is selected based on the Input range selected in the Delsig ADC component(for VSSA - VDDA range) and voltage(VSSA) configuration is CYDWR file. When VSSA - VDDA input range is selected, the reference is configured to be VDDA/3 or VDDA/4(this depends on CYDWR setting). The input to be measured (input to the ADC) is attenuated to obtain input/4 or input/3. The attenuated input is then compared against the reference and digitised.