Anyone know anything about Arduino / ATTiny / USB CDC ?

[Jon Russell]

Hi,

I have some DigiSpark boards (http://digistump.com/products/1) for a project, to use as LED indicators. I need them to be driver install free, and naively thought the ATTiny's had hardware USB.

It seems they don't and use VUSB (https://www.obdev.at/products/vusb/index.html) to emulate USB on GPIO in software .

However, the sample CDC code they provide doesn't work on Windows 10, I get USB errors.

I think the VUSB code is not setting the correct USB device descriptor headers, but thats way beyond my understanding / skill ?

Anyone here every developed any embedded USB, or use VUSB on ATTinys that might like to help me in the right direction ?

Thanks.

Jon.

[Stephen Casey]

Hi Jon,

No direct experience of VUSB, but I came upon this, and wondered if it's any help:

https://m.reddit.com/r/AskElectronics/comments/2x8xt6/having_trouble_with_vusb_attiny85_device_not/

Good luck.

Steve.

[Stefan Sabo]

The best place at HackSpace to this question is specific ML of "Not Just Arduino" group, where will be significant more chance to get positive response.

https://groups.google.com/forum/#!forum/not-just-arduino

I am not sure, if their regular meeting take place this morning, or next week, refer please to calendar. It  is also good opportunity to take some advice and kick out ideas. 

[Nick Johnson]

CDC isn't technically supported on USB low speed, which is all VUSB can emulate. You'd be better off using HID, which is also going to be install-free on all OSes, unlike CDC.

-Nick

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[Jon Russell]

Hi.

Yes. I read that. However I need to write small amounts of data to this thing and all the HID examples I've seen are read only, like keyboards, mice, etc. Do you happen to know of a HID device that can be written to?

Thanks.

Jon.

[Tomasz Mloduchowski]

Actually - keyboards are read-write (yeah, I was surprised myself by that years ago).

The CapsLock/ScrollLock/NumLock state is actually a bi-directional HID register. Standard keyboard drivers completely accept expanding that field arbitrarily - and custom HID interfaces go way beyond and can implement complex state transitions.