1. VDD_5V: Supply voltage, range:4.7 ~ 5.6V. We recommend a 5V/1.2A(MAX) power. You can lower the clock to decrease the power consumption. When the clock is lowered by 200MHz the power consumption roughly decreases 0.5W .
2. BOOT_CS: Boot chip selection. When it is not connected or pulled up the board boots from eMMC otherwise it boots from SD card
3. NRESETIN: Reset input. Activated when it is low. A reset signal is input to CPU from this pin
4. NRESETOUT: Reset output. Activated when it is low. CPU's reset signal outputs to this pin.
5. RTC_BATT: RTC's input, direct connection to a 3V power source. If the CPU board is powered on the RTC seat is powered by 3.3V external power otherwise when the CPU board is not powered on it is powered by the RTC battery.
6. ADC1~7: CPU internal ADC, 12-bit, 7 channels 1~7, range:0 ~ 1.8V
7. 10/100M Ethernet mode: LAN_MDI1_N/P=RX-/+, LAN_MDI0_N/P=TX-/+, four pins connected to RJ45
8. 10/100/1000M Ethernet mode: LAN_MDI0_N/P~LAN_MDI3N/P, all eight pins connected to RJ45
9. Smart4418 Schematic in pdf