Re: [usb] Corrupted Ack during Last Burst In Transaction

["Vishal Namshikar" <vishaln@controlnet.co.in>]

regarding QUESTION : How host can be sure
I dont think host need to know whether ACK has been received by device
without error.
When IN token is given to the endpoint again device will respond with same
packet (in case ACK was not received by it).
There will be data toggle mismatch error and data will be neglected by host.
But ACK packet will be given to device which will help it to advance its
toggle bit.

----- Original Message -----
From: <PeGe@mail.ru>
To: <usb@opencores.org>
Sent: Friday, April 25, 2003 5:00 PM
Subject: [usb] Corrupted Ack during Last Burst In Transaction


> Sorry for poor English ;)
>
> Host reads data (Bulk transactions) from USB device.
> ..
> When host need to read last portion of data,
> he send IN packet,
> device send DATA packet,
> host receives it with out error and send ACK packet
>
> Question:  How host can be sure,
> that device received ACK packet without error?
>
> For example, if host reads from FIFO (USB device),
> how he can be sure, that he reads all data from it?
> And FIFO become epmty !!!
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