Objective Development Forums

Hello Christian!
Im doing my project in university about USB communication, im a beginer of USB so that i were lacked of knowlege of USB. Now, im doing the USB led fader project but i met some problems in working process, i used Atmega16 instead of Atmega8 as in the project's schematic, i added the "test supply voltage" led but when i connected it to the USB port then on the Window Xp there was not anything happen, also didnt appear "USB device not recognised". Can you tell me the solution for this problem?
Moreover, when i added the led to the circuit, the led wouldnt light if i connect the Vcc pin of microcontroller to Vdd of USB port but when i removed it (the Vcc pin out of Vdd) it would light???
Sorry for my E!
Thank you in advance!
Best regard!

If Windows does not even display the "device not recognized" message, you have a hardware problem. A simple pull-up of 1.5 k from Vcc to D- is sufficient to get this message.

I don't understand your other question, though. If you connect your device to USB, the power LED does not light. But if you disconnect it, it goes on? How can this be, if no power supply is available?

sorry for my E!
i mean that when i connected the Vcc pin of Atmega16 to Vdd of USB port the led didnt light but when i disconnected it the led did light!i didnt remove the led out of Vdd of USB port.
And do i need to install new driver for this project?

Sorry, I don't know the project so I can't comment on the function of the "test supply voltage" LED. However, if Windows does not bring up ANY alert, there is no 1.5k pull-up between the supply and D-, or the AVR outputs low level on D+ and D-.

I suggest u to check all parts of your hardware, last time my hardware didn't work because the diodes were bad (short circuit) i had to replace they and then the hardware works again. Also remember that D+ must be connect to INT0 if u use a different pin port of the project default.

I used DevC++ to compile the files and create the .exe file to run the application from command line. I get to work two leds of the usb led fader but the other two leds didn't work for me. I must check it later

Daniel Barragan
Argus Smart - Parquesoft
danielbcr.blogspot.com