I am using stm32f407 for my project. I am very new to stm32f4 discoveries board. I am using HAL drivers for this.I want to use external ADC with 24 bit resolution (Texas Instruments PCM1808q). After getting reading from a pressure sensor. I checked different example on internet but yet to find an suitable one. Can anyone help me in this for starters.

 

All in the datasheet.

 

24 bits adc to measure pressure seems to me an extreme overkill.
You move with 24 bits in all type of problems with power supply ref voltage and shielding.
for pressure 12 or 16 bit is normally more than enough (ref voltage)/(2^16)
The accuracy is NOT the number of bits but the stability of the reference voltage.
The density is defined by the number of bits in the adc.
At 24 bits (ref voltage)/(2^24) now you might end up in the Nano volts that will put you into problems with layout power all things mentioned above. (imagine that your ref voltage has a ripple of 1 micro volt and no special provision is made ...... what happened to the output?)