@me-no-dev but, like i described befoure the TOUT can be used for only one think, VDD mesaurement OR analogRead. The way for choose this is changing and uploading the init bin file whit the right value on it (33 for analogread and 255 for VddRead).
But this core actually do not support this function.
So if on the ESPboard is uploaded from factory the init bin file whit the AnalogRead function active, we cannot use system_get_vdd33.

My pullrequest is only for analogRead problem, and it work. Only after the init bin file uploading function added to this core we can have a good readVdd function.

For the analogReference also is there two way that we can choose, whitout the argument it is unusefull, so what you prefer ? I prefer have an error during compilation instead of a good compilation but no clear/working analogReference function.

@igrr is it very difficult adding the init bin file uploading ? this is the real solution and we can create a final version of core_esp8266_wiring_analog.c file.
we can create two version of init bin file, and when the user use analogRead, or system_get_vdd33 the correct init bin file will be uploaded