USB-device on ATMega8.

General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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uchar
Posts: 15
Joined: Wed Oct 28, 2009 12:05 pm

USB-device on ATMega8.

Post by uchar » Wed Oct 28, 2009 12:42 pm

Prompt please, whether probably to make the USB-device on chip ATMega8, using the built in RC-generator?

christian
Objective Development
Objective Development
Posts: 1443
Joined: Thu Nov 09, 2006 11:46 am

Re: USB-device on ATMega8.

Post by christian » Wed Oct 28, 2009 4:46 pm

You can use the 12.8 MHz version on the Mega8 with the built-in RC oscillator.

Guest

Re: USB-device on ATMega8.

Post by Guest » Sun Nov 01, 2009 2:29 am

I try to use autocalibration algorythm for ATMega8 and it does not work. Maybe because ATMega8 with the built-in RC oscillator has initial frequency 8Mhz

Guest

Re: USB-device on ATMega8.

Post by Guest » Sun Nov 01, 2009 2:36 am

I was run hid-mouse example after set calibration register to 226 value (manually). But calibration algorythm calculate another value for 12Mhz non-crystal Atmega8 (I see it in EEPROM), and device does not recognize :(

christian
Objective Development
Objective Development
Posts: 1443
Joined: Thu Nov 09, 2006 11:46 am

Re: USB-device on ATMega8.

Post by christian » Sun Nov 01, 2009 10:48 am

If you use the 12.8 MHz module (the 12 MHz module won't work because it requires an EXACT clock rate), you also need to add the oscillator calibration. There are two types, see the libs-device directory in the driver distribution. The calibration will tune the oscillator from 8 MHz to 12.8 MHz.

Guest

Re: USB-device on ATMega8.

Post by Guest » Mon Nov 02, 2009 6:52 pm

I understand, but calibration does not work properly. OSCAL value is incorrect after calibration and device does not recognized

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