[SOLVED]Device somewhy recognized as full speed

General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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Evgeny
Posts: 1
Joined: Sun Jan 04, 2009 7:53 pm

[SOLVED]Device somewhy recognized as full speed

Post by Evgeny » Sun Jan 04, 2009 8:04 pm

Hello.

I have a little problem with hardware part of avr-usb. My device is recognized as 'full speed', though afaik it should recognize as low speed.
I use Zener diode level conversion. 1.3k resistor between Vcc and D-, 3.3v zeners. I try with 3.3v because I have working USBasp with same 3.3v diodes and 1.3k resistor.

The question is: is there any chance to get stuff working as it is now, or exact 3.6v and 1.5k are necessary?

dmesg output:

Code: Select all

usb 3-1: device descriptor read/64, error -71
usb 3-1: device descriptor read/64, error -71
usb 3-1: new full speed USB device using uhci_hcd and address 85
usb 3-1: device descriptor read/64, error -71
usb 3-1: device descriptor read/64, error -71
usb 3-1: new full speed USB device using uhci_hcd and address 86
usb 3-1: device not accepting address 86, error -71
usb 3-1: new full speed USB device using uhci_hcd and address 87
usb 3-1: device not accepting address 87, error -71
hub 3-0:1.0: unable to enumerate USB device on port 1


EDIT:
I will NEVER EVER use NON-STANDARD usb cables! The one I used is non-standard(different marking for D+ and D-), so I got them swapped -> resistor went to wrong one.

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