RM0082
HS_USB2.0 host
Doc ID 018672 Rev 1
445/844
22.6.28 HcInterruptStatus
register
This register provides status on various events that cause hardware interrupts. When an
event occurs, Host Controller sets the corresponding bit in this register. When a bit becomes
set, a hardware interrupt is generated if the interrupt is enabled in the HcInterruptEnable
register (see Section 7.1.5) and the MasterInterruptEnable bit is set. The Host Controller
Driver may clear specific bits in this register by writing ‘1’ to bit positions to be cleared. The
Host Controller Driver may not set any of these bits. The Host Controller will never clear the
bit.
[01]
CLF
0b
R/W
R
ControlListFilled
This bit is used to indicate whether there are any TDs on
the Control list. It is set by HCD whenever it adds a TD to
an ED in the Control list.
When HC begins to process the head of the Control list, it
checks CLF. As long as ControlListFilled is 0, HC will not
start processing the Control list. If CF is 1, HC will start
processing the Control list and will set ControlListFilled to
0. If HC finds a TD on the list, then HC will set
ControlListFilled to 1 causing the Control list processing to
continue. If no TD is found on the Control list, and if the
HCD does not set ControlListFilled, then ControlListFilled
will still be 0 when HC completes processing
the Control list and Control list processing will stop.
[00]
HCR
0b
R/W
R
HostControllerReset
This bit is set by HCD to initiate a software reset of HC.
Regardless of the functional state of HC, it moves to the
USBSUSPEND state in which most of the operational
registers are reset except those stated otherwise; e.g., the
InterruptRouting field of HcControl, and no Host bus
accesses are allowed. This bit is cleared by HC upon the
completion of the reset operation.The reset operation
must be completed within 10 ms. This bit, when set,
should not cause a reset to the Root Hub and no
subsequent reset signaling should be asserted to its
downstream ports.
Table 368.
HcCommandStatus register bit assignments (continued)
Bits
Name
Reset
Read/Write
Description
HCD
HC