Author Topic: usb function  (Read 13615 times)

yalect

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usb function
« on: March 23, 2014, 07:57:20 am »
thank you Mr Jan Axelson for Previous replys, I understand that each of D+ and D- works like out or in for type of transfer from begining at numeration, will not change after, and which Usually of them is in and other is out ?
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Jan Axelson

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Re: usb function
« Reply #1 on: March 23, 2014, 12:23:45 pm »
No, low, full, and high speeds all use differential signaling. Differential zero is when D+ is logic low and D- is logic high as defined by the USB 2.0 spec. Differential one is when D+ is logic high and D- is logic low as defined by the USB 2.0 spec. Data travels in one direction at a time.

See 7.1.7 in the USB 2.0 spec.

yalect

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Re: usb function
« Reply #2 on: March 26, 2014, 04:13:06 am »
Hi, you mean we can't use term of in and out for D+ or D- or clearly (Pin in) and (Pin out) not standard for example for usb 2.0 or I can say Dout and Din ?
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Jan Axelson

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Re: usb function
« Reply #3 on: March 26, 2014, 10:18:39 am »
No, Dout and Din are not accurate descriptions. Both lines carry data in both directions.

yalect

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Re: usb function
« Reply #4 on: April 16, 2014, 07:27:02 am »
I understood that after numeration of device, D+ can works in and out data together and the same for D- or each one can works in direction ( during operating of  one device)   
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Jan Axelson

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Re: usb function
« Reply #5 on: April 16, 2014, 09:23:17 am »
This might help in understanding how the interface works:

http://en.wikipedia.org/wiki/Differential_signaling