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V-USB on AtTiny2313
unofficial-fish Posted: 18 Jun 2024, 12:48 AM
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I have copied the standard schematic you use with V-USB, as it requires minimal components. I have figured out how to program and use the chip but unfortunately the default V-USB examples don't seem to work with that design. I have tried to modify the configuration of the examples to make it work, with no luck. Do you have any pointers? Thanks!
(Also, I've had two chips become unresponsive to programming so far, perhaps they really do mean it with the static warning on the bag...)

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mit Posted: 19 Jun 2024, 10:40 AM
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yeah whatever

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I think you'll need to give more info, in what way do they not work? which ones did you try? Which schematic are you trying?

I'm not sure I ever ran V-USB on an ATtiny2313, which is much more limited than the ATtiny85 and its siblings. Note the attiny2313 doesn't have a PLL so you won't be able to do the oscillator calibration trick, you'll need a crystal.

I don't think I've ever destroyed an AVR chip to ESD, I've definitely killed them in other ways but it usually was very obvious. It might be that you ran the oscillator calibration code and it tried to set it to some strange value. Try connecting at a really slow speed (like avrdude -B50) and erasing the eeprom.

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unofficial-fish Posted: 22 Jun 2024, 06:24 PM
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I had not considered that despite having a bigger number and more pins, the 2313 would have less capabilities. It makes sense when I think about the numbering now...
Anyhow, I copied the design from the tiny laser cutter dongle at https://mitxela.com/img/uploads/etchpcb/eagle1.png as closely as I could. The (hardly readable) result:
(User posted image)

and the breadboard version (may be slightly different, as I was messing around trying to make it work):
(User posted image)

That one I was just trying to run the "move mouse in circle" demo on. And yes, the picture is uselessly blurry, my webcam is not up to this task.

Is there a chip that has a 7 pin port and the capabilities of the ATTiny85? I think a redesign from scratch is necessary here, and all I want out of it is something like that USB dongle with 7 buttons attached (to make a basic USB gamepad.)

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mit Posted: 22 Jun 2024, 09:46 PM
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yeah whatever

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It's a long time since I've looked at it, you're best off looking at the datasheets, but from memory I think the 85 series was the only one with the 16MHz PLL. You can run V-USB on the other chips just by fitting a quartz crystal though.

Alternatively you could go with the CH32V003 and CNLohr's USB stack, which does a similar thing to V-USB. It's what I used for the USB-C midi synth.

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unofficial-fish Posted: 16 Nov 2024, 07:52 PM
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I just happened to be scrolling through the site recently and noticed that in https://mitxela.com/projects/rc_tx_usb_joypad_2 you used the ATtiny861, which would appear to be what I need (minimal extra components required for V-USB, sufficent pins). Do you think that would work? So far as I can tell it's a perfect fit, but I have little experience. Thanks!

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mit Posted: 17 Nov 2024, 05:53 PM
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yeah whatever

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There is (or was) a wikipedia page that compared the ATtiny chips which was helpful to give a quick overview of what supported what. But yeah, if I already ran V-USB on the 861 then that seems to answer your question.

I really really recommend just reading the datasheets for the parts. They tell you everything. That was always the best bit about the AVR chips, that the datasheets were very good. Just one PDF told you everything you need to know - unlike certain other manufacturers.

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