The HiFi Shield Plus provides both stereo RCA connectors to connect to external amplifiers and other audio equipment. Via TI’s high-end PCM5242 DAC chip(known as Burr-Brown), it supports 16, 24, 32 bit audio formats with minimal THD+N ratio (0.002%) and ideal dynamics (114dB+), plus amazing sampling rates of 384kHz
U3 IO Shield is the board that can be plugged on the neat of ODROID-U3 via tiny 8 pin IO connector. You can have 36 IO ports of GPIO/PWM/ADC. The shape and dimension are exactly same as ODROID-U3. It comes with 12pcs of PCB spacers for easier and solid stacking assembly.
RTC backup battery Lithium primary battery to back up the RTC on XU board. This battery can keep the RTC running up to 5 years without external power supply.