Jumper
Boot Mode (P10 & P11)¶
Helios64 SoC supports 3 boot modes that can be chosen by jumper configuration.
The default boot device order is:
- SPI Flash
- eMMC Flash
- micro-SD Card
The SoC will access sequentially the above devices until it finds a bootloader code. To change the boot order if a bootloader code is present on more then one device, we can use the combination of P10 and P11 jumpers to force SoC to skip devices.
- P11 jumper can be used to disable SPI Flash, when this jumper is shorted SoC will skip looking for bootloader on SPI Flash and will continue with the EMMC Flash.
- P10 jumper can be used to disable eMMC Flash, when this jumper is shorted SoC will skip looking for bootloader on eMMC Flash and will continue with the micro-SD card.
The following logic table gives a simplified view of boot order configuration by jumper, assuming bootloader code is present on each device:
| P11 State | P10 State | Boot Order | Notes |
|---|---|---|---|
| 0 | 0 | SPI Flash | - |
| 1 | 0 | eMMC Flash | - |
| 1 | 1 | micro-SD Card | - |
USB Console/Recovery Mode (P13)¶
This jumper controls a 2:1 MUX switching the USB2.0 lanes of the Type-C port (J15) between the SoC Type-C interface and the USB-to-Serial bridge. For more details refer to the USB Type-C section.
- When the jumper is opened the Type-C port (J15) can be used to connect to the serial console of the Helios64.
- When closed and system in recovery mode, the Type-C port (J15) can be used to flash directly the eMMC over USB.
DC-IN Priority (P15)¶
Helios64 supports 2x different DC-IN 12V inputs :
- AC Adapter (J16)
- ATX PSU (J10)
You can plug both DC-IN inputs in order to have a failover setup that automatically switches to the other input if the first one fails. Jumpers P15 can be used to force ATX as master DC-IN input.
| P15 | Description |
|---|---|
| Open | O-Ring Connection |
| Close | Set ATX Priority |
SATA Controller Flash (P8)¶
Reserved for production.
eFuse Power Enable (P9)¶
When shorted this jumper will allow user to burn efuse data in order to configure secure boot.
Warning
Wrong efuse data can bricked Helios64 which cannot be repaired. Do NOT short this jumper if you don't know what you are doing.