Downstream USB ports

General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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Frotz
Posts: 1
Joined: Tue Jun 02, 2009 5:17 am

Downstream USB ports

Post by Frotz » Tue Jun 02, 2009 5:31 am

I'm tinkering with V-USB to create a drop-in driver board replacement for the IBM Model M. Following the existing projects for this is well and good, but I want to add two downstream USB ports to the board, mainly for connecting a mouse and card-swiper. The Dulcimer at http://www.schatenseite.de/dulcimer.html?L=2 uses an ATmega32 and uses up all the available pins. Assuming I find an ATmega of some sort with enough pins to drive some downstream ports, will the chip have enough horsepower to do this? Alternatively, would someone please suggest something to run as a USB hub?

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

Re: Downstream USB ports

Post by christian » Fri Jun 05, 2009 5:38 pm

The AVR is roughly 10 times too slow for this. USB hosts must implement Full Speed USB (12 MBit).

Your best option is probably to buy a cheap USB hub, crack the case and build it into your device.

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