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harbaum / I2C-Tiny-USB

Cheap and simple I²C to USB interface
http://www.harbaum.org/till/i2c_tiny_usb
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Adafruit Trinket M0 supported? #20

Closed UweSauter closed 3 years ago

UweSauter commented 3 years ago

On the Adafruit Trinket home is a deprecation warning, advising users to change to the Adafruit Trinket M0. Is this also supported by this firmware?

What changes would be necessary to support the Trinket M0?

prandeamus commented 3 years ago

I will make a guess. The original trinket uses an ATTINY85 and the M0 uses a much more sophisticated processor ATSAMD21E18. Getting to ATTINY85 to bitbang USB is an amazing feat of cleverness, but it stretches the chip to do low-speed USB and sometimes there are timing problems with individual chips or USB controllers. The ATSAMD21E18 is described as having native USB so I suppose much more is implemented in hardware & should be more reliable.

But the ATSAMD21E18 is a much different processor and therefore would require different firmware than an ATTINY85.

(If I'm wrong, I'm wrong. But that's how I read it)

harbaum commented 3 years ago

That's correct. The i2c-tiny-usb makes extensive use of the attiny85's features.

It may be possible to write a compatible firmware for the trinket m0. But this sure needs to be written explicitly for the m0.

UweSauter commented 3 years ago

Would you put this info into your README.md so that other visitors can get it while reading the project description?