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Section 26 USB 2.0 Host/Function Module
Page 1488 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
(b) When the host controller function is selected and when the connection is used in which
split transactions occur
(i) For the pipe in the transmitting direction:
For the pipe for isochronous transfers, when the time to issue an OUT token comes in a
state in which there is no data to be transmitted in the FIFO buffer.
In this case, this module transmits a zero-length packet following the OUT token, setting
the corresponding PIPENRDY bit and the OVRN bit to 1 at the issuance of the start-split
transaction (S-SPLIT).
For the pipe for the transfers other than isochronous transfers, when any combination of the
following two cases occur three consecutive times: 1) no response is returned from the
HUB for the S-SPLIT or complete-split transaction (C-SPLIT) (when timeout is detected
before detection of the handshake packet from the HUB) and 2) an error is detected in the
packet from the HUB.
In this case, this module sets the PIPENRDY bit of the corresponding pipe to 1 and
modifies the setting of the PID bits of the corresponding pipe to NAK.
If the NRDY interrupt is detected when the C-SPLIT is issued, this module clears the
CSSTS bit to 0.
When the STALL handshake is received in response to the C-SPLIT.
In this case, this module sets the corresponding PIPENRDY bit to 1, modifies the setting of
the PID bits of the corresponding pipe to STALL (11) and clears the CSSTS bit to 0.
This interrupt is not detected for SETUP transactions.
When the NYET is received in response to the C-SPLIT and the microframe number = 4.
In this case, this module sets the corresponding PIPENRDY bit to 1 and clears the CSSTS
bit to 0 (does not modify the setting of the PID bits).
(ii) For the pipe in the receiving direction:
For the pipe for isochronous transfers, when the time to issue an IN token comes in a state
in which there is no space available in the FIFO buffer.
In this case, this module discards the received data for the IN token, setting the
corresponding PIPENRDY bit and the OVRN bit to 1 at the issuance of the S-SPLIT.
During bulk-pipe transfers or the transfers other than SETUP transactions with the DCP,
when any combination of the following two cases occur three consecutive times: 1) no
response is returned from the HUB for the IN token issued by this module at the issuance
of S-SPLIT or C-SPLIT (when timeout is detected before detection of the DATA packet
from the HUB) and 2) an error is detected in the packet from the HUB.