NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 727 -
Revision V1.30
NUC97
0
T
E
CHNIC
A
L
RE
F
E
RE
N
CE
MA
NUA
L
USB Command Register (UCMDR)
Register
Offset
R/W
Description
Reset Value
UCMDR
0x020
R/W
USB Command Register
0x0008_0000
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
ITC
15
14
13
12
11
10
9
8
Reserved
7
6
5
4
3
2
1
0
Reserved
IAAD
ASEN
PSEN
FLSZ
HCRST
RUN
Bits
Description
[31:24]
Reserved
Reserved.
[23:16]
ITC
Interrupt Threshold Control (R/W)
This field is used by system software to select the maximum rate at which the host
controller will issue interrupts. The only valid values are defined below. If software writes
an invalid value to this register, the results are undefined. Value Maximum Interrupt
Interval
0x00 = Reserved.
0x01 = 1 micro-frame.
0x02 = 2 micro-frames.
0x04 = 4 micro-frames.
0x08 = 8 micro-frames (default, equates to 1 ms).
0x10 = 16 micro-frames (2 ms).
0x20 = 32 micro-frames (4 ms).
0x40 = 64 micro-frames (8 ms).
Any other value in this register yields undefined results.
Software modifications to this bit while HCHalted bit is equal to zero results in undefined
behavior.
[15:7]
Reserved
Reserved.