UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
517 of 1269
NXP Semiconductors
UM10503
Chapter 23: LPC43xx USB0 Host/Device/OTG controller
7
SRI
SOF received
0
R/WC
0
This bit is cleared by software writing a one to it.
1
When the device controller detects a Start Of
(micro) Frame, this bit will be set to a one. When
a SOF is extremely late, the device controller will
automatically set this bit to indicate that an SOF
was expected. Therefore, this bit will be set
roughly every 1 ms in device FS mode and every
125
s in HS mode and will be synchronized to
the actual SOF that is received. Since the device
controller is initialized to FS before connect, this
bit will be set at an interval of 1ms during the
prelude to connect and chirp.
8
SLI
DCSuspend
0
R/WC
0
The device controller clears the bit upon exiting
from a Suspended state. This bit is cleared by
software writing a one to it.
1
When a device controller enters a Suspended
state from an active state, this bit will be set to a
one.
11:9
-
-
Reserved. Software should only write 0 to
reserved bits.
12
-
-
Not used in Device mode.
0
13
-
-
Not used in Device mode.
0
14
-
-
Not used in Device mode.
0
15
-
-
Not used in Device mode.
0
16
NAKI
NAK interrupt bit
0
RO
0
This bit is automatically cleared by hardware
when the all the enabled TX/RX Endpoint NAK
bits are cleared.
1
It is set by hardware when for a particular
endpoint both the TX/RX Endpoint NAK bit and
the corresponding TX/RX Endpoint NAK Enable
bit are set.
17
-
-
Reserved. Software should only write 0 to
reserved bits.
0
-
18
-
Not used in Device mode.
0
-
19
-
Not used in Device mode.
0
-
31:20
-
-
Reserved. Software should only write 0 to
reserved bits.
-
Table 402. USB Status register in device mode (USBSTS_D - address 0x4000 6144) register bit description
Bit
Symbol
Value
Description
Reset
value
Access