SH7720 Datasheet, PDF (847/1524 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 24 USB Host Controller (USBH)
24.3.17 Hc Periodic Start Register (USBHPS)
USBHPS has a 14-bit programmable value, which determines the earliest time when the host
controller should start to process the periodic list.
Initial
Bit
Bit Name Value R/W Description
31 to 14 
All 0 R Reserved
These bits are always read as 0. The write value should
always be 0.
13 to 0 PS13 to PS0 All 0 R/W Periodic Start
This field is cleared after the hardware has reset. Then
this field is set by HCD while the host controller performs
initial settings. The value is roughly calculated as the value
of the USBHFI minus 10%. When USBHFR reaches the
specified value, the processing of the periodic list has a
higher priority than the control/bulk processing.
Consequently, the host controller starts to process the
interrupt list after the completion of the current control/bulk
transaction.
Rev. 3.00 Jan. 18, 2008 Page 785 of 1458
REJ09B0033-0300