General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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Guest
Post
by Guest » Mon May 26, 2008 2:20 pm
Hi
I want to run atmega at 5V but I don't have Zener diodes and regulators on hand.
Is it OK if connect the USB power at pin 1 to atmega Vcc, and connect 2 diodes, 1 68 ohm resistor at D- pin, so that output of atmega pin is dropped to 3.x V ?
Thank you very much.
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christian
- Objective Development
- Posts: 1443
- Joined: Thu Nov 09, 2006 11:46 am
Post
by christian » Wed May 28, 2008 5:26 pm
Try to omit the zener diodes. Most hosts accept 5 V levels. If that does not work, add two series diodes in the supply to drop the voltage to approx. 3.6 V. That's the cheapest solution.