Re: [usb] In token pid's

["Vikas T Rao " <vikasraot@myw.ltindia.com>]

** Proprietary **

hi govind,

the 1st data packet of the data phase during the control transfer will always start with DATA1. the succeeding data packets in the same data phase will have their data toggle values alternatively i.e. 2nd packet - DATA0, 3rd packet - DATA1 and so on.

so, the data phase for the GET_CONFIGURATION command will have only one data packet(one byte in it) which has data toggle value as DATA1.

for bulk IN commands, the 1st data packet from the device will have DATA0 and then this value toggles for succeeding packets. even though a series of control transfers take place in between these bulk transfers, the data toggle values will be maintained. this is because each endpoint will have it's own data toggle bit. so, irrespective of the other endpoints data toggle bits, the data toggle bit on a particular endpoint will not change(exception ofr EP0).

....vikas

>>> govindsrajan@hotmail.com 06/18/02 10:42PM >>>
Hello folks,

    If the host sends an IN token during a control xfer, for a
    Get_Configuration command, (or any of the Get .. commands)
    what is the pid sent by the device? Is it DATA0 or DATA1 or 
    can it be any of these. Also during Bulk_IN commands, what
    is the pid send by the device.

    Thanks
    Govind
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