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Message
From: mdennis97@h...
Date: Thu, 13 Feb 2003 09:12:29 -0100
Subject: Re: [usb] how to detect if a valid handshake is received
----- Original Message -----
From: "Vikas T Rao " <vikasraot@m... >
To: <usb@o... >
Date: Wed, 12 Feb 2003 10:15:34 +0530
Subject: Re: [usb] how to detect if a valid handshake is received
>
>
> hi,
>
> host will wait for 16 bit times (USB 1.1) to receive an ACK packet
> from
> the device.
>
> whenever device expects ACK, it will wait for 16 bit times(also
> called
> timeout interval). supposing device has received a corrupted ACK
> packet
> before the timeout interval, it will have to understand that it is
> ACK
> packet. if timeout interval has occured and some corrrupted packet
> has
> been received, then it should be some token packet only but not ACK
> packet from the host.
>
> now if host expects an ACK packet, it will wait for timeout
> interval.
> if a corrupted packet is received before this timeout period, host
> will
> have to definitely begin with the same token packet that has been
> sent
> lastly. this is because host will not know whether device has sent
> ACK,
> NAK or STALL.
>
> r u clear now???
>
> ...vikas.
>
>
>
> >>> mdennis97@h... 02/11/03 02:59PM >>>
> hi,all
>
> If a device answer no handshake at all,how long a host will wait?
> How to identify a corrupted ACK handshake that mentioned in usb1.1
> specifiction 8.6.4?
>
>
>
>
>
>
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> I am clear now.Thank you very much.
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