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Block Diagram

Helios4 Carrier Board

Block Diagram

A388 System-On-Chip

Block Diagram

Connector / Interface List

Board Legend

Name Peripheral Type Connector Type Details
CON2 Serial port Micro-USB Connector Via onboard FTDI USB-to-UART0 bridge
J8 RC Battery Not populated External battery source for RTC clock
J9 I2C 4x1 Pin Male Header I2C Bus 1
J10 Fan 4x1 Pin Male Header PWM and RPM support
J12 GPIO 7x2 Pin Male Header GPIO configurable as input or output
Via IO Expander on I2C Bus 0
J13 Serial port Not populated SoM UART0 interface
J14 HDD Power Molex 4-Pin Female Rated for 2x HDD
J15 LAN RJ45 Gigabit Ethernet
J16 DC connector Kycon 4-Pin Mini-DIN DC input 12V / 8A
J17 Fan 4x1 Pin Male Header PWM and RPM support
J18 LED Panel 5x2 Pin Male Header Expansion port of on-board LED
J19 HDD Power Molex 4-Pin Female Rated for 2x HDD
SW1 Boot Mode Dip Switch Boot mode selector :
SW2 LED Mode Dip Switch LED mode selection :
board or expansion panel
U3 microSD Push-Push card connector Support SDHC and SDXC
U4 USB 3.0 Dual Port USB3.0 Type A
U16 Reset Push Button CPU Reset
U10 SATA SATA 3.0 Port 0 (SATA1)
U11 SATA SATA 3.0 Port 1 (SATA2)
U12 SATA SATA 3.0 Port 2 (SATA3)
U13 SATA SATA 3.0 Port 3 (SATA4)

Boot Modes

Helios4 supports 4 boot modes that can be chosen by using the dipswitch SW1.

Dipswitch modes

All the ready-to-use images we provide are for the SD Card boot mode.

Please refer to U-boot section to know how to use the other modes.

LED indicators

LED Name Color Description
LED1 green System heartbeat
LED2 red Error status
LED3 green SATA1 activity
LED4 green SATA2 activity
LED5 green SATA3 activity
LED6 green SATA4 activity
LED7 green USB activity
LED8 green Power indicator

Helios4 board was designed to either use the on-board LEDs or use an expansion panel (not-available). To use the on-board LEDs insure to switch to ON the dipswitch SW2.

Dipswitch LED

Reset Button

Helios4 board provides a RESET push button (U16) to hard reset the SoC (System-On-Chip).

Reset Button


This button only resets the SoC and not the overall board. For instance it won't reset the HDD.

I2C Interface

Helios4 board exposes on header J9 the SoC I2C Bus 1. Below is the header pin-out, the little arrow on the PCB indicates the ground pin.

I2C Pinout

Power Consumption

Board only

  • Idle : 3.6 Watts
  • Active : 5.6 Watts

Full Kit (with 4x HDDs)

State AC calculated
power consumption
DC measured
power consumption
Idle 19.3 W 16.8 W
HDD Read Access 27.4 W 22.8 W
HDD Write Access 30.3 W 25.2 W
Standby 8.0 W 6.7 W HDD in Standby mode
Suspend-to-Ram 7.2 W 6.0 W HDD in Standby mode


Measures were done using a Current Clamp Meter on the Helios4 12V DC input. AC Power consumption is calculated based on a AC/DC conversion efficiency of 85%.

  • Meter tool : Extech 380942 - 30A True RMS AC/DC Mini Clamp
  • AC/DC Adapter : yczx1268 (efficiency : 85%)
  • AC Input Voltage: 220V
  • HDD: 4x WD Red 2TB (WD20EFRX) configured as RAID10
  • Network : Connected at 1000Mb/s
  • OS: ARMBIAN 5.73 stable Debian GNU/Linux 9 (stretch) 4.14.98-mvebu

HDD Recommendation List

We recommend HDD which are designed for NAS (Network Attached Storage). Those NAS HDD are specially conceived for reliable 24/7 operation and offers lower power consumption and dissipation, less vibration and noise, and finally better warranty. We recommend the following brands / families :

  • Western Digital : WD Red NAS
  • Seagate : IronWolf NAS
  • HGST : Deskstar NAS
  • Toshiba : NAS N300


We recommend to order from different shop to avoid having all the drives from the same factory batch. For instance, you should order 2x HDDs from one shop, then the 2 others from another shop.

Last update: May 2, 2020