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Compatibile USB devices

PostPosted: Sat Apr 30, 2011 12:46 pm
by Char27
Starting a new topic for general USB compatibility discussions...

USB over Wireless
This looks really cool but I am wondering if the power consumption is too high- requires 1w@5vdc.
http://www.amazon.com/Cables-Unlimited- ... B0036VNZHA

I may get one (if its not too slow for general use) but want some thoughts on the power usage before I would test it with this.
Don't want to fry my A2 or the board. What is the power limit of the 3000 for USB?

Re: Compatibile USB devices

PostPosted: Mon May 02, 2011 9:37 am
by david__schmidt
I would test it with regular computers first. The power is one issue, but software support is another one. I picked up a USB device that promised to make one computer act/appear like a disk drive to the other side of the USB cord. I thought that would be a really cool way to use the CFFA3000. But the trouble is... it requires software on both ends in order to work. That's fine on the PC/Mac end, but it's a non-starter on the CFFA3000 end. If it doesn't look just like a storage device at the outset, it's not going to work.

Re: Compatibile USB devices

PostPosted: Mon May 02, 2011 10:30 pm
by Char27
What! No Windows or Linux driver support? :)

I will read some more reviews before I consider it. Needs to be useful for other devices too before I spend the money.
Do you know if a high power spec will just mean it won't work or can it damage the the card/A2? I don't know much about USB power and if OHMs vary by device potentially causing stuff to heat up if its not limited in some way.
Thanks

Re: Compatibile USB devices

PostPosted: Tue May 03, 2011 4:21 pm
by rich
Hi Guys,

In theory the USB power switch on the board would handle 14Watts @ a voltage drop of 185mv.
This means a current of 2.8Amps. I would reduce that spec to 1Amp for safety and given the trace
widths on the PCB itself. Also note that there is NO overload protects on this board so
if you short the USB 5v supply you are shorting the Apple II's supply via the CFFA3000.
Typically the PCB traces will then be acting like fuses and "smoke" the CFFA3000.

Also, although it is possible that the CFFA3000 may grow to support other devices, in the beginning
it will support USB mass storage devices and nothing else. So don't assume it will support other things.

-Rich

Re: Compatibile USB devices

PostPosted: Sat May 07, 2011 1:13 am
by toinet
rich wrote:Hi Guys,

Also, although it is possible that the CFFA3000 may grow to support other devices, in the beginning
it will support USB mass storage devices and nothing else. So don't assume it will support other things.

-Rich


Hello Rich,
Will you "open source" the firmware of the card or what are your plans? Adding keyboard or mouse support would be fun.
I would like to see something more open than the iDisk I have and with which I cannot play anything but disk images.

Antoine
(and congratulations for the card)