SH7205 Datasheet, PDF (1326/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 24 USB 2.0 Host/Function Module (USB)
When an IN token is received, if the buffer memory is in the transmission enabled state, this
module transmits the data. If the buffer memory is not in the transmission enabled state, however,
a zero-length packet is sent and an underrun error occurs.
Figure 24.14 shows an example of transmission using the isochronous transfer transmission data
setup function with this module, when IITV = 0 (every frame) has been set. Sending of a zero-
length packet is displayed in the figure as Null, in a shaded box.
Received token
Buffer A
Empty
Writing
Buffer B
Sent packet
IN
IN
Writing ended
Empty
Null
Null
IN
Transfer enabled
Empty
Data-A
SOF packet
Buffer A
Buffer B
Empty
Writing Writing ended
Empty
Writing
Transfer enabled
Writing ended
Received token
Buffer A
Buffer B
Sent packet
IN
Empty
Writing Writing ended
Empty
Writing
Null
IN
Transfer
enabled
Empty
Writing ended
Data-A
IN
Writing
Writing ended
Transfer
enabled
Empty
Data-B
Received token
Buffer A
Buffer B
Sent packet
IN
Empty
Writing Writing ended
Empty
Writing
Null
IN
IN
IN
Transfer
enabled
Empty
Writing ended
Writing
Writing ended
Transfer
enabled
Empty
Data-A
Null
Data-B
Figure24.14 Example of Data Setup Function Operation
Rev. 1.00 Mar. 25, 2008 Page 1294 of 1868
REJ09B0372-0100