Arduboy FX ATtiny85

I can’t tell from the pictures if the Arduboy FX (not the modded one) has an ATtiny85 on board. Could you please confirm?


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The production Arduboy FX will not have an ATtiny85 on board.

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The attiny is only there to update the bootloader, so you don’t need an external programmer. The factory made FX will come with the bootloader installed.

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@Mr.Blinky @bateske thank you for the answer. I was hoping to use it to offload some code execution from the main core.

Anyway being not on the FX I assume that it will not be a supported use case in the official library. Am I correct?

The sole role for the Attiny is an easy method for updating the bootloader and bootloader recovery. There will be no library support for it. It wouldn’t be useful for offloading code anyway.

Thank you for the answer, I think there was a topic along the lines of what I am asking in past but I might be wrong.

What is the interface in between the two uC?

I believe you mean this:

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Actually I found what I was referring to:

The thread was started by you @Pharap :wink:

But I am not sure of the outcome of that… hence I was asking on why it disappeared from the main design. I had a use-case similar to sound offload in mind.

… the mod chip is for sale. This exists.

As mentioned before the attiny reprograms the bootloader. It is not needed on the factory built ones because it already has the bootloader.

I missed that question. There was no main design. There was one design goal and talking of ideas like adding a sound generator. But thinking more about that a MCU with more features would be prefered and things would become more complex.

So In the thought of let’s keep things simple and let’s get started. I chose on using an attiny85 as I got some lying around (The firmware was written to fit an attiny45 though. As the first prototype modchips had one of those).

Not moving to the newer generation of attiny’s ment I could use my ISP code for both Arduboy and the Attiny as the newer ones require the UPDI programming method.

Communication is purely done using ISP protocol over the shared SPI bus:

  • Arduboy ISP’s Attiny firmware.
  • Arduboy ISP’s Attiny EEPROM with flash bootloader command
  • Attiny ISP’s Arduboy bootloader

OP is confused between the self bootloading mod chip and the final “Arduboy FX” factory made version.

@Mr.Blinky Thank you for the exhaustive explanation. Based on what you said since there is no support on the “Arduboy FX” factory mode version, I would end up fragmenting the code I am planning to write if I offload any functionality, hence I might need to rethink it a bit.

@bateske Maybe we could add the differentiation in the product page since there is no mention of “Arduboy FX” factory mode version and both the versions listed report what below:

  • Peripheral Microcontroller (ATtiny85) – An additional microcontroller is along for the ride for the sole purpose of flashing the bootloader to the Arduboy. This eliminates the

I noticed it looking at the pictures but I think it is easy to miss :wink: What do you think?

Thank you to both for your time :slight_smile: