What type adc is to be interfaced with lpc2478
my project involves acquisition of physiological signals like temperature,ecg,these signals to be amplified and converted to digital form.Digital signals are to processed by arm lpc2478 and to be displayed on lcd.So,i need a suggestion for choosing adc to interface lpc2478 and what type of communication is needed for interfacing external adc with arm lpc2478. how much resolution is required for displaying real time display of ecg.