Hi Hamid,
Yes, you would use the DRDY pin to drive a hardware interrupt. Inside the interrupt routine you would change the mux/read the data. Also, you would disable any other interrupt from taking place while you capture the data, and re-enable the interrupts when you exit.
You do as little as possible within the interrupt, and only what is required. You would also need to have some global variables that you can use to keep track of what data has been collected, for the selected MUX settings.
Best regards,
Bob B