USB Host Controller Registers
14-21
Universal Serial Bus Host
The HC head bulk register defines the local bus virtual address of the head ED
on the bulk ED list.
Table 14–12. HC Head Bulk Register (HcBulkHeadED)
Bit
Name
Description
Type
Reset
Value
31–4
BHED
Local bus virtual address of head ED on the bulk ED list
This field represents bits 31:4 of the local bus virtual address
of the head ED on the bulk ED list. EDs are assumed to
begin at 16-byte-aligned address, so bits 3:0 of this pointer
are assumed to be 0. See See Section 14.6.1, Local Bus
Addressing, for the restrictions on local bus virtual
addresses.
R/W
0
3–0
Reserved
Reserved
R
0x0
The HC current bulk register defines the local bus virtual address of the next
ED on the bulk ED list.
Table 14–13. HC Current Bulk Register (HcBulkCurrentED)
Bit
Name
Description
Type
Reset
Value
31–4
BCED
Local bus virtual address of current ED on the bulk ED list
This field represents bits 31:4 of the local bus virtual address
of the next ED on the bulk ED list. EDs are assumed to begin
at 16-byte-aligned address, so bits 3:0 of this pointer are
assumed to be 0. See See Section 14.6.1, Local Bus
Addressing, for the restrictions on local bus virtual
addresses.
A value of 0x0000000 indicates that the USB host controller
has reached the end of the bulk ED list without finding any
transfers to process.
This register is automatically updated by the USB host
controller.
R/W
0
3–0
Reserved
Reserved
R
0x0