hi,
how can i use more as the 12ADC inputs?
is there a code example?
how many ADC are maximum=
πxl
You can look at mux/demux chips, HC4051 for example, https://www.ti.com/lit/ds/symlink/cd74hct4051.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1679568010621&ref_url=https%253A%252F%252Fwww.mouser.ch%252F
Or PCF8591 ADC chips: Overview | Adafruit PCF8591 Basic 4 x ADC + DAC Breakout | Adafruit Learning System
Or many others.
What resolution do you want? The Uno, say, has a 10bit ADC.
At what frequency are you going to collect samples? 10 per second or what ?
How do you want to talk to the chips? via I2C or SPI or what ?
EDIT
The Pinout of the STM32H747XIH6 based Arduino GIGA is here: https://content.arduino.cc/assets/ABX00063-full-pinout.pdf and general information available here: Arduino GIGA R1 WiFi — Arduino Official Store
The data sheet for the STM32H747XIH6 chip https://www.st.com/resource/en/datasheet/stm32h747xi.pdf speaks of three 16bit ADCs giving up to 36 channels. You may be able to configure some internal port multiplexer to bring out some more ADC channels but probably not without some impact on the Arduino rest of the Arduino environment.
thank you 6v6gt
i read somewhere that its possible to configuren at least the DAC0/1 pins as additional ADC's in - thats why i ask. (maybe 14 ADC's are enough for my purposes)
πxl
Hi @pixl_noise . Pins A0-A11 are dedicated ADC pins, but you can also use the DAC0 & DAC1 as ADC pins, bringing the total to 14 analog input pins. 
thank you.
whats the way to do this?
simple "analogRead(A12)" doesnt work. it looks like noise from open analog pins, but no change if i connect to ground or to 3.3V: