Hi, I am looking for some advice about interfacing ads8323 at 500ksps to STM32F427 MCU without using extra hardware (maybe some glue logic) to have the minimum overhead for MCU to gather the data. Thanks!

Of course you could connect the digital signals to GPIOs of a MCU.

But I see two issues:

This is a 5V device, you would need levelshifters.

A 500ksps sample rate is easily managed via a serial connection. No commercial project would waste so much pins, and go for a SPI-based ADC instead.

Thanks! This is a 16-bit parallel ADC that I need to use but my question is mostly firmware overhead. What is the best way to connect this parallel ADC to STM to have the minimum overhead on firmware. I am asking from experts who used parallel ADCs with STM.