V-USB on Attiny 85 with internal 8MHz oscilator

[open-nandra]

Hi,

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

[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. OR you can use the PLL clock doubler and run on 16.5 MHz.

[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.

[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.

[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.

[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.