BootloadHID with ATmega8 schematic

General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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6TIT
Posts: 2
Joined: Mon Mar 17, 2008 11:59 am

BootloadHID with ATmega8 schematic

Post by 6TIT » Mon Apr 21, 2008 11:43 am

Hello,

I've build a test-board with this schematic.
I regulated the data lines with two zener-diodes.

http://www.obdev.at/products/avrusb/bootloadhid.html

When I connect it to the pc he doesn't recognise him.
Now could it be that I need to regulate the supply voltage to 3.6 and not the data lines? Or could there be something else wrong ?

I've seen schematics where the supply voltage is reduced:
==> http://www.obdev.at/products/avrusb/hidkeys.html
==> http://www.obdev.at/products/avrusb/index.html
==> http://www.obdev.at/products/avrusb/hidkeys.html

I wish to know some opinions before I start changing things on my test-board.


Greetz...

The schematic I made:
==> http://www.avrfreaks.net/index.php?name ... ic&t=62894

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

Post by christian » Mon Apr 21, 2008 7:00 pm

The schematic should be OK, if the Zener diodes are OK. Please measure the voltage on D- with a voltmeter. It should be well above 2.5 V.

Guest

Post by Guest » Mon Apr 28, 2008 11:47 am

Its about 2.9V so thats correct.....

I programmed the bootloader again (with STK500)
(I didn't change anything in the firmware or such because I am using a regulary ATmega8)


but it still doesn't recognize the device.


Any Idea's left :cry: ?

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

Post by christian » Mon Apr 28, 2008 4:06 pm

Did you check the obvious things:
- fuse bits
- hardware configuration reflected in bootloaderconfig.h
- compiled for correct clock rate
- boot loader enabled by jumper

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