Can I just connect the Attiny85 to a usb port without any usb to serial adapter? Because All the tiny attiny85 based devboards like Adafruit trinket doesn't seem to have those U2S adapters - in fact, the attiny85 is the only chip on the board, others are all components like resistors or leds. Anyways can I add a usb port to my attiny85 devboard just by soldering the two directly together? On my atmega328 breadboard arduinos I had to program them with the adafruit ftdi friend
There is an extension to the arduino IDE that will allow these to act as USB devices, they also have a small bootloader on board so they can be programmed directly from the IDE
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You can if you put code based on vusb ( this is a way of faking usb - it's not standards compliant, but almost always works) - normally this is done in the bootloader, since people want to program it over usb. This takes up a significant amount of flash that you could otherwise use for your code.
There are a few other hardware components you need (resistors and zener diodes) for vusb.
V-USB is a software trick to connect to USB1.1 protocol. DigiSpark and Trinket are likely the 2 best commercial products. But the trick also works on the Atmega328P.
The single most critical component in the USB interface are 2x 3.6V zener diodes.
I have several V-USB projects here.
Other forum links:
Here and here
Ray
can I somehow connect an attiny85 or atmega328 to a usb a port??? without any special chips like ftdi??
Using VUSB, yes. Not sure how easy / hard to use with arduino. It's a little flaky, compatibility is marginal, but it does mostly work (despite making a mockery of the spec). Be sure you understand the limitations by carefully reading the documentation.
I recommend using a chip that has native usb on it though, like the 32u4
PocketHarambe101:
can I somehow connect an attiny85 or atmega328 to a usb a port??? without any special chips like ftdi??
you mean like the CH430G and CP2102 USB to TTL Serial converters?
Yes.
Maybe you should consider changing the subject of your post to give a little more meaning.
The type of USB-port does not matter - it's the role of the port being the host that is important here.
// Per.