How to use EOS in Companion Mode (with external host processor)

[marbu]

Hey,

the chapter on system Startup (p. 291 ref manual) is very sparse on how to use the EOS in combination with an external host processor.
The manual also denotes it as Companion Mode.
I would like to know if
+ it is necessary to load the firmware via the SPI Slave interface on every system boot cycle
or which other boot modes are available
+ there is any further documentation about the Companion Mode and/or examples on how to flash the EOS by the host processor

Thank you!

[plowhank]

In the configuration you describe, it is often necessary to load the EOS firmware via the SPI Slave interface during each system boot cycle. This necessity arises from the nature of Companion Mode.

level devil

[AnnJennings]

Navigating system startup can feel like scaling a steep hill, much like in the Slope Game where precision is key. The reference manual's section on EOS and external host processors, particularly in Companion Mode, leaves some questions unanswered. Do we always need to load firmware via SPI Slave on boot? Are there alternative boot options? And where can we find more detailed documentation or examples for flashing the EOS using the host processor? Any guidance would be greatly appreciated.

[alehyha]

In Companion Mode, the EOS is typically booted by an external host. In this case, the firmware must be loaded via the SPI slave interface on every power-up, as the EOS does not automatically boot a persistent image by itself.

Other boot options (e.g. standalone boot from external flash) exist, but those are intended for standalone operation, not Companion Mode.

At the moment, there is no separate public documentation specifically for Companion Mode. The intended flow is described indirectly in the Technical Reference Manual, mainly in the SPI slave and boot sequence sections. Flashing or loading firmware is expected to be handled entirely by the host processor using SPI.