Completion of Either
SETUP Phase or
OUT Data Phase
ReqPkt
and StatusPkt
Both Set?
Yes
IN Token Sent
STALL
Received?
Yes
RxStall Set
ReqPkt Cleared
Error Count Cleared
Interrupt Generated
Command Could Not
Be Completed
No
No
NAK
Received?
No
Yes
No
NAK Limit
Reached?
Yes
Yes
No
No
NAK Timeout Set
Endpoint Halted
Interrupt Generated
DATA1
Received?
Error Count
Incremented
ACK Sent
RxPktRdy Set
Transaction
Complete
Implies Problem at
Peripheral End of
Connection
Transaction Deemed
Completed
Error Bit Set
ReqPkt Cleared
Error Count Cleared
Interrupt Generated
Yes
Error Count
= 3?
ReqPkt Cleared
Error Count Cleared
Interrupt Generated
Error Count
Cleared
Functional Description
STALL response.
If ERROR bit is set, it means that the controller has tried to send the required IN token three times
without getting any response.
If NAK_TIMEOUT bit is set, it means that the controller has received a NAK response to each attempt
to send the IN token, for longer than the time set in the HOST_NAKLIMIT0 register. The controller can
then be directed either to continue trying this transaction (until it times out again) by clearing the
NAK_TIMEOUT bit or to abort the transaction by clearing REQPKT bit and STATUSPKT bit before
clearing the NAK_TIMEOUT bit.
4. The CPU should clear the STATUSPPKT bit of HOST_CSR0 together with (i.e., in the same write
operation as) RxPktRdy if this has been set.
Figure 16-11. Flow Chart of Status Stage of Zero Data Request or Write Request of a Control Transfer in
Host Mode
16.3.8.2.1.5 Status Phase for a Read Request of a Control Transaction: Host Mode
OUT Status Phase of a control transfer exist for a Read Request or a control transfer where data was
received by the host controller. The OUT Status phase follows the IN Data Stage of a control transfer.
For the OUT Status Phase of a control transaction (
), the CPU driving the host device needs
to:
1724
Universal Serial Bus (USB)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated