Alan Stern writes: > Yes, it is possible. Your circuit must provide 1.5 KOhm (+/-5%) > resistor tied to a voltage source between 3.0 V and 3.6 V, and connected > to the USB D+ data line (D- if you want to use low-speed signalling > instead of full-speed). For more details see the USB 2.0 specification.
My guess is actually that it won't be possible: that the interface to the USB controller is high-level enough that it actually isn't possible to send an arbitrary bit stream out the port. It's certainly the case that this is impossible with the eight-bit USB processors (like ST7) that I've looked at; I'd be really surprised if a PC could do it. > If you do this, you will find the computer does send data to your circuit. > However the USB drivers expect every attached device to provide responses > to requests, which your circuit will not do. As a result the drivers will > disable the USB port and you won't be able to send any useful data. If he can get low-enough level control of the port to send arbitary bits, then he can get it to read arbitrary bits too. -- Joseph J. Pfeiffer, Jr., Ph.D. Phone -- (505) 646-1605 Department of Computer Science FAX -- (505) 646-1002 New Mexico State University http://www.cs.nmsu.edu/~pfeiffer ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
