Filter
Top Products
Section 26 USB 2.0 Host/Function Module
R01UH0134EJ0400 Rev. 4.00 Page 1541 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
IN IN
Data-A
IN
Data-B
IN IN
Data-A
IN
Data-B
IN
IN IN IN
Data-A
Zero-
length
Zero-
length
Zero-
length
Zero-
length
SOF
SOF
SOF
SOF SOF
SOF SOF SOF
SOF
SOF SOF
SOF
SOF
Zero-
length
Empty
(1) Reception start 1 (transmit data is prepared before IN token reception starts)
Received token
Packet to be
transmitted
Buffer A
Buffer B
Empty Writing Writing ended Transfer enabled
Empty Writing Writing ended
(2) Reception start 2 (example 1: transmit data is prepared after IN token reception starts)
Received token
Packet to be
transmitted
Buffer A
Buffer B
Empty Writing Writing ended Transfer enabled Empty
Empty
(3) Reception start 2 (example 2: transmit data is prepared after IN token reception starts)
Received token
Packet to be
transmitted
Buffer A
Buffer B
Empty Writing Writing ended Transfer enabled Empty Writing Writing ended
Empty Writing Writing ended Transfer enabled Empty
(4) IN token reception at the frame other than the specified interval
Received token
Packet to be
transmitted
Buffer A
Buffer B
Empty Writing Writing ended Transfer enabled Empty Writing Writing ended
Empty Writing Writing ended Transfer enabled
Figure 26.20 Example of Data Setup Function Operation
(5) Isochronous Transfer Transmission Buffer Flush when the Function Controller
Function is Selected
If an SOF packet or a SOF packet is received without receiving an IN token in the interval frame
during isochronous data transmission, this module operates as if an IN token had been corrupted,
and clears the buffer for which transmission is enabled, putting that buffer in the writing enabled
state.
If a double buffer is being used and writing to both buffers has been completed, the buffer
memory that was cleared is seen as the data having been sent at the same interval frame, and
transmission is enabled for the buffer memory that is not discarded with SOF or SOF packets
reception.