RM0082
HS_USB2.0 host
Doc ID 018672 Rev 1
441/844
divided into four partitions, specifically for Control and Status, Memory Pointer, Frame
Counter and Root Hub. All of the registers should be read and written as Dwords.
Reserved bits may be allocated in future releases of this specification. To ensure
interoperability, the Host Controller Driver that does not use a reserved field should not
assume that the reserved field contains 0. Furthermore, the Host Controller Driver should
always preserve the value(s) of the reserved field. When a R/W register is modified, the
Host Controller Driver should first read the register, modify the bits desired, then write the
register with the reserved bits still containing the read value. Alternatively, the Host
Controller Driver can maintain an in-memory copy of previously written values that can be
modified and then written to the Host Controller register. When a write to set/clear register is
written, bits written to reserved fields should be 0.
22.6.24
The control and status partition
22.6.25 HcRevision
register
22.6.26 HcControl
register
The HcControl register defines the operating modes for the Host Controller. Most of the
fields in this register are modified only by the Host Controller Driver, except
HostControllerFunctionalState and RemoteWakeupConnected.
Table 366.
HcRevision register bit assignments
Bits
Name
Reset
Read/Write
Description
HCD
HC
[31:08]
Reserved
[07:00]
REV
8’h10
R
R
Revision
This read-only field contains the BCD representation of
the version of the HCI specification that is implemented by
this HC.
For example, a value of 11h corresponds to version 1.1.
All of the HC implementations that are compliant with this
specification will have a value of 10h.
Table 367.
HcControl register bit assignments
Bits
Name
Reset
Read/Write
Description
HCD
HC
[31:11]
--
Reserved
[10]
RWE
0b
R/W
R
RemoteWakeupEnable
This bit is used by HCD to enable or disable the remote
wakeup feature upon the detection of upstream resume
signaling. When this bit is set and the ResumeDetected bit
in HcInterruptStatus is set, a remote wakeup is signaled to
the host system. Setting this bit has no impact on the
generation of hardware interrupt.