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Section 26 USB 2.0 Host/Function Module
R01UH0134EJ0400 Rev. 4.00 Page 1451 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
Bit Bit Name
Initial
Value R/W Description
1, 0 PID[1:0] 00 R/W Response PID
Specifies the response type for the next transaction
of the pertinent pipe.
00: NAK response
01: BUF response (depending on the buffer state)
10: STALL response
11: STALL response
The default setting of these bits is NAK. Modify the
setting to BUF to use the pertinent pipe for USB
transfer. Tables 26.12 and 26.13 show the basic
operation (operation when there are no errors in the
transmitted and received packets) of this module
depending on the PID bit setting.
After modifying the setting of these bits from BUF to
NAK during USB communication using the pertinent
pipe, check that PBUSY is 0 to see if USB
communication using the pertinent pipe has actually
entered the NAK state. However, if the PID bits have
been modified to NAK by this module, checking
PBUSY is not necessary.
After S-SPLIT is issued (CSSTS = 1) for split
transaction in the pertinent pipe, the transaction
continues until C-SPLIT is completed even when the
PID bits are set to NAK.
This module modifies the setting of these bits as
follows.
This module sets PID to NAK on recognizing the
completion of the transfer when the pertinent pipe
is in the receiving direction and the SHTNAK bit
for the selected pipe has been set to 1.
This module sets PID to STALL (11) on receiving
the data packet with the payload exceeding the
maximum packet size of the pertinent pipe.
This module sets PID to NAK on detecting a USB
bus reset when the function controller function is
selected.