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RE: [usb] USB protocol questions
Rudolf,
1. Ignore the ping from host.
2a. See 7.1.18 7.5 bit time for FS/LS and 192 bit time for HS.
2b and 2c. See 8.6 Data Toggle Synchronization and Retry. The two
conditions fall under the same category. The function shall not toggle the
data token in next transmission.
3. I can not find a timeout on this.
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email me using pteng@mail.com, pteng@yahoo.com or peter_teng@el.nec.com, or
please call me direct. Sorry in advance for the trouble that may caused you.
best regards,
"Peter" Chu Tin Teng
Computing technology I/O Group
NEC Electronics Inc.
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-----Original Message-----
From: owner-usb@opencores.org [mailto:owner-usb@opencores.org]On Behalf
Of Rudolf Usselmann
Sent: Saturday, January 13, 2001 6:37 AM
To: USB Mailing List
Subject: [usb] USB protocol questions
I have a few USB protocol questions. I would appreciate references
to the specification with your answers !
1) When operating in FS mode, PING tokens are not allowed.
a) Should the function report PING tokens to it's controller?
b) Should it reply to PING just as would in HS mode?
c) Should it just ignore PING in FS mode?
2) When the function received an IN token, and sends DATA back
to the host, the host will reply with an ACK if it accepted
the data.
a) What is the time-out period in which the host has to reply?
b) If the host did not reply, what should the function do?
c) If the ACK from the host becomes corrupt and the function
ignores it, how should it proceed?
3) When a function receives an out token, the next packet will
be a DATA packet.
a) What is the time-out period for waiting for the data packet?
Thanks a lot !
rudi