NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 730 -
Revision V1.30
NUC97
0
T
E
CHNIC
A
L
RE
F
E
RE
N
CE
MA
NUA
L
USB Status Register (USTSR)
Register
Offset
R/W
Description
Reset Value
USTSR
0x024
R/W
USB Status Register
0x0000_1000
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
ASS
PSS
RECLA
HCHalted
Reserved
7
6
5
4
3
2
1
0
Reserved
IAA
HSERR
FLR
PCD
UERRINT
USBINT
Bits
Description
[31:16]
Reserved
Reserved.
[15]
ASS
Asynchronous Schedule Status (RO)
The bit reports the current real status of the Asynchronous Schedule. If this bit is a zero
then the status of them Asynchronous Schedule is disabled. If this bit is a one then the
status of the Asynchronous Schedule is enabled. The Host Controller is not required to
immediately disable or enable the Asynchronous Schedule when software transitions the
Asynchronous Schedule Enable bit in the USBCMD register. When this bit and the
Asynchronous Schedule Enable bit are the same value, the Asynchronous Schedule is
either enabled (1) or disabled (0).
[14]
PSS
Periodic Schedule Status (RO)
The bit reports the current real status of the Periodic Schedule. If this bit is a zero then the
status of the Periodic Schedule is disabled. If this bit is a one then the status of the
Periodic Schedule is enabled. The Host Controller is not required to immediately disable or
enable the Periodic Schedule when software transitions the Periodic Schedule Enable bit
in the USBCMD register. When this bit and the Periodic Schedule Enable bit are the same
value, the Periodic Schedule is either enabled (1) or disabled (0).
[13]
RECLA
Reclamation (RO)
This is a read-only status bit, which is used to detect an empty asynchronous schedule.
[12]
HCHalted
HCHalted (RO)
This bit is a zero whenever the Run/Stop bit is a one. The Host Controller sets this bit to
one after it has stopped executing as a result of the Run/Stop bit being set to 0, either by
software or by the Host Controller hardware (e.g. internal error).
[11:6]
Reserved
Reserved.
[5]
IAA
Interrupt on Async Advance (R/WC)
System software can force the host controller to issue an interrupt the next time the host
controller advances the asynchronous schedule by writing a one to the Interrupt on Async
Advance Doorbell bit in the USBCMD register. This status bit indicates the assertion of
that interrupt source.