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V-USB on Attiny 85 with internal 8MHz oscilator

Posted: Thu Sep 17, 2009 10:06 am
by open-nandra
Hi,

I'ts possible to use V-USB at attiny 85 with internal 8MHz oscillator?
Thanks

Re: V-USB on Attiny 85 with internal 8MHz oscilator

Posted: Tue Sep 22, 2009 10:58 am
by christian
8 MHz is out of question. But you can use 12.8 MHz with the internal oscillator (it can be tuned up to 12.8) OR you can use the PLL clock doubler and run on 16.5 MHz.

Re: V-USB on Attiny 85 with internal 8MHz oscilator

Posted: Fri Dec 11, 2009 10:21 pm
by kevin
Would this be a (relatively) simple matter of configuring constants within the driver, or require extensive modification to the driver code?
Trying to decide which microcontroller to use for a 4 button "keyboard", so the bandwidth and I/O requirements are minimal.

Re: V-USB on Attiny 85 with internal 8MHz oscilator

Posted: Fri Dec 11, 2009 11:04 pm
by christian
12.8 MHz and 16.5 MHz are a matter of constant definition (F_CPU) plus additional calibration code from the libs-device directory.

8 MHz is not possible, in my opinion. However, if somebody is able to implement an 8 MHz module with PLL, this would be a complete rewrite of the assembler part.

Re: V-USB on Attiny 85 with internal 8MHz oscilator

Posted: Wed Jan 20, 2010 8:37 pm
by dany_87
Hi,

I am using the Arduino Duemilanove and I want to install the V-USB software on it, the board has a 16 MHZ clock speed. I am just not sure of the steps that should be done to be able to use the board as a USB. I am a newb in using the arduino.I downloaded the latest version of V-USB from here "http://obdev.at/products/vusb/download.html", but I am not sure of how to proceed after that. If anyone can tell me the steps it would be a great help.

Thanks in advance.

Re: V-USB on Attiny 85 with internal 8MHz oscilator

Posted: Wed Jan 20, 2010 9:43 pm
by christian
If you want to use V-USB, I'd recommend to forget about the Arduino IDE and write your code directly in C. Arduino comes with the C development environment.

It is possible to use V-USB with the Arduino runtime, but it's not well documented and does not work reliably (yet). So I'd not recommend it for beginners.