Hello, > -----Ursprüngliche Nachricht----- > Von: Greg KH [mailto:greg@;kroah.com]
> Yes, you need a special USB device/client/gadget controller chip in > order to get a "PC" to be a USB device, that's just the way > the hardware works. > > That being said, there are a _lot_ of cheap USB device controllers out > there that you can choose from to put on a custom board. We had the same challenge to go for. But not a scanner ;-) We use a pc platform as measuring system and this gadget is connected to usb as usb device. We decided to run an ETX board with Pentium 266MHz, using Linux standard kernel 2.4.18, and connected a Philips ISP1181A on the 16-bit wide ISA bus. PCI would be pretty more complicated and ISA runs fast enough to go Full Speed. ISP1181A supports 80ns write cycle time and got lots of double buffered endpoints (14 programmable) at low cost. A cheaper one is Philips PDIUSBD12, but this one only got 2 bulk endpoints with 64 bytes double buffered fifo. That often doesn't do any harm, but the cycle time of the D12 is 600ns, which is farely low, and the bus is only 8 bit wide. So we got transfer rates with D12 up to 400 kByte/s, but 780 kByte/s with ease with ISP1181. Be aware that our cpu does a lot more than feeding the usb buffers. Only about 15% is reserved for the usb driver. As far as I can say now, I'd like to publish that code for both chips by GPL. Ask me if you are interested. Even if you might find some errors, this is a pretty good thing to start from, ain't it? Siegfried. ------------- HBM - Hottinger Baldwin Messtechnik GmbH Siegfried Wessler, Dipl.-Ing. Development Amplifiers T-V Im Tiefen See 45, D-64293 Darmstadt, Germany Fon: +49/6151/803-884, Fax: -524 eMail: [EMAIL PROTECTED] ------------------------------------------------------- This sf.net email is sponsored by: See the NEW Palm Tungsten T handheld. Power & Color in a compact size! http://ads.sourceforge.net/cgi-bin/redirect.pl?palm0001en _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
