Registers
1594
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Serial Bus OHCI Host Controller
33.3.9 HC Head Control Register (HCCONTROLHEADED)
The HC head control register (HCCONTROLHEADED) defines the physical address of the head endpoint
descriptor (ED) on the control ED list. HCCONTROLHEADED is shown in
and described in
.
Figure 33-10. HC Head Control Register (HCCONTROLHEADED)
31
16
CHED
R/W-0
15
4
3
0
CHED
Reserved
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 33-10. HC Head Control Register (HCCONTROLHEADED) Field Descriptions
Bit
Field
Value
Description
31-4
CHED
0-FFF FFFFh Physical address of the head ED on the control ED list. This field represents bits 31-4 of the
physical address of the head ED on the control ED list. EDs are assumed to begin on a 16-byte
aligned address, so bits 3-0 of this pointer are assumed to be 0. For the restrictions on physical
addresses, see
3-0
Reserved
0
Reserved
33.3.10 HC Current Control Register (HCCONTROLCURRENTED)
The HC current control register (HCCONTROLCURRENTED) defines the physical address of the next
endpoint descriptor (ED) on the control ED list. HCCONTROLCURRENTED is shown in
and
described in
Figure 33-11. HC Current Control Register (HCCONTROLCURRENTED)
31
16
CCED
R/W-0
15
4
3
0
CCED
Reserved
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 33-11. HC Current Control Register (HCCONTROLCURRENTED) Field Descriptions
Bit
Field
Value
Description
31-4
CCED
0-FFF FFFFh Physical address of the current ED on the control ED list. This field represents bits 31-4 of the
physical address of the next ED on the control ED list. EDs are assumed to begin on a 16-byte
aligned address, so bits 3-0 of this pointer are assumed to be 0. For the restrictions on physical
addresses, see
A value of 0 indicates that the USB1.1 host controller has reached the end of the control ED list
without finding any transfers to process. This register is automatically updated by the USB1.1 host
controller.
3-0
Reserved
0
Reserved