SH7760 Datasheet, PDF (773/1345 Pages) Renesas Technology Corp – SuperHTM RISC engine

Bits Bit Name Initial Value R/W Description
3
IE
0
R/W Isochronous Enable
This bit is used by HCD to enable/disable the
processing of isochronous ED. While processing the
periodic list, HC will check the status of this bit when
it finds an isochronous ED (F =1). When this bit is 1
(enabling), HC continues to process ED. When this
bit is 0 (disabling), HC stops the processing of the
periodic list (currently including only isochronous ED)
and starts to process the bulk/control list. Setting this
bit is guaranteed to be valid in the next frame (not in
the current frame).
0: Isochronous list processing is disabled in the next
frame
1: Isochronous list processing is enabled in the next
frame
2
PLE
0
R/W Periodic List Enable
This bit is set to 1 to enable processing of the
periodic list. When HCD clears it to 0, no periodic list
processing is carried out after next SOF. HC must
check this bit before HC starts to process the list.
0: Periodic list processing is disabled in the next
frame
1: Periodic list processing is enabled in the next
frame
1
CBSR1
0
0
CBSR0
0
R/W Control Bulk Service Ratio
R/W _{This specifies the service ratio between Control and}
Bulk EDs. Before processing any of the nonperiodic
lists, HC must compare the ratio specified with its
internal count on how many nonempty Control EDs
have been processed, in determining whether to
continue serving another Control ED or switching to
Bulk EDs. The internal count will be retained when
crossing the frame boundary. In case of reset, HCD
must restore this value.
00: The ratio of Control ED to Bulk ED is 1:1
01: The ratio of Control ED to Bulk ED is 2:1
10: The ratio of Control ED to Bulk ED is 3:1
11: The ratio of Control ED to Bulk ED is 4:1
Rev. 1.0, 02/03, page 723 of 1294