On Wed, 17 May 2006, vkataev wrote: > Hi all, > I have a question: > > Is it possible to send a sequence of the bytes just into an USB-Port ?
I think you mean "out from a USB port". The port is on the computer, and the computer is sending the data out. > I have a small electrical circuit. It is attached to USB output and it > has no any IC controller. So I just want to get a simple sequence of the > bytes from my computer, for instance: > 10101010101010101.... > or > 111000111000111000111000... > to be processed with my primitive fully non-digital circuit. Note that data on a USB bus is not encoded simply as 0s and 1s. USB uses NRZI encoding with bit stuffing, CRC, and framing bits. Your primitive non-digital circuit probably will not be able to understand it. > It's just flooding into USB port. My computer's mainboard has 2 USB > ports, would be fine if I can select one. > > Is it possible ? In the case of a positive answer: HOW? No matter how > hard it could be, please give me know. 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. 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. Alan Stern ------------------------------------------------------- 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
