YaCh,
I'm back.
I performed some experiments and have some suggestions.
Attached is a project based on your original design intent. It has three schematic sheets. Enable only one sheet at a time. Disable the enabled sheet first, then enable the next sheet. Perform a build.
The application in main() switches the AMux_1 one channel every 1 second and displays the mV reading using the DEBUG_UART @ 115.2Kps.
The "sch" is a modification of your original design (See pic below). I included 3000mV and 500mV VDAC sources to drive the channels 0 and 1 of AMux_1.
The 1.024V Vref is not AutoEnabled. The resultant channel 3 voltage reading is 1824mV. There is also a Opamp follower mode on the output of the AMux_1 to see the result of the mux on a scope.
The "VDAC" sheet (See pic below) replaces the 1.024V Vref with a VDAC generating 1.020V. The resultant channel 3 reading is about 1042mV. This is more on target.
The final "VFD" sheet (See pic below) keeps the 1.024V Vref on channel 3 with it AutoEnable'd. It does replace Comp_1, Comp_2, Comp_3 and Comp_4 with a 4-channel VFD component. The resultant channel 3 voltage is about 1042mV. I did not fully configure the VFD so it may not be working to intended spec.
By the way, Cypress provides a PowerMonitor that provides ADC readings and input voltage fault detection of various types.
Maybe one of these ideas will work for you.
Len
