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smiles
Joined: 27 Jul 2007
Posts: 104
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 20 Aug 2008 3:05 USB 's data lines |
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from USB Complete, I read this statement, could you explain me more about it
"USB’s two signal lines carry data to and from all of the devices on the bus.
The wires form a single transmission path that all of the devices must share.
Unlike RS-232, which has a TX line to carry data in one direction and an RX line for the other direction, USB’s pair of wires carries a single differential signal, with the directions taking turns."
How data travel through these two lines ???
Thanks !!!
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sakthivel.s
Joined: 22 Jan 2008
Posts: 9
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| 08 Sep 2008 9:51 Re: USB 's data lines |
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| In RS232, seperate lines are available for RX and TX where as in USB only D+ and D- lines available which is called differential pair. To repersent '1' D+ line go to high(5 V) and D- line go to low(0V) and viceversa.
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useless_skew
Joined: 19 Nov 2007
Posts: 49
Helped: 5
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| 08 Sep 2008 11:53 Re: USB 's data lines |
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In USB, the data transmission is done using a differential pair cable (Like RS-485).
Full duplex communication cannot take place. There is a master-slave concept in USB. Only the master can initiate a transfer. The slave should moniter the bus for activities. If the master requests for data from a slave/sends out a data to the slave,
the slave must acknowledge it and process the request.
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