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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
651 of 1441
NXP Semiconductors
UM10503
Chapter 25: LPC43xx/LPC43Sxx USB0 Host/Device/OTG controller
25.6.3.2 Host mode
13
SUTW
Setup trip wire
During handling a setup packet, this bit is used as a semaphore to ensure
that the setup data payload of 8 bytes is extracted from a QH by the DCD
without being corrupted. If the setup lockout mode is off (see USBMODE
register) then there exists a hazard when new setup data arrives while the
DCD is copying the setup data payload from the QH for a previous setup
packet. This bit is set and cleared by software and will be cleared by
hardware when a hazard exists. (See
).
R/W
0
14
ATDTW
Add dTD trip wire
This bit is used as a semaphore to ensure the to proper addition of a new
dTD to an active (primed) endpoint’s linked list. This bit is set and cleared
by software during the process of adding a new dTD. See also
.
This bit shall also be cleared by hardware when its state machine is hazard
region for which adding a dTD to a primed endpoint may go unrecognized.
R/W
0
15
-
Not used in device mode.
-
-
23:16
ITC
Interrupt threshold control.
The system software uses this field to set the maximum rate at which the
host/device controller will issue interrupts. ITC contains the maximum
interrupt interval measured in micro-frames. Valid values are shown below.
All other values are reserved.
0x0 = Immediate (no threshold)
0x1 = 1 micro frame.
0x2 = 2 micro frames.
0x8 = 8 micro frames.
0x10 = 16 micro frames.
0x20 = 32 micro frames.
0x40 = 64 micro frames.
R/W
0x8
31:24
-
Reserved
0
Table 469. USB Command register in device mode (USBCMD_D - address 0x4000 6140) bit description
…continued
Bit
Symbol
Value
Description
Access
Reset
value
Table 470. USB Command register in host mode (USBCMD_H - address 0x4000 6140) bit description - host mode
Bit
Symbol
Value
Description
Access Reset
value
0
RS
Run/Stop
R/W
0
0
When this bit is set to 0, the Host Controller completes the current
transaction on the USB and then halts. The HC Halted bit in the
status register indicates when the Host Controller has finished the
transaction and has entered the stopped state. Software should not
write a one to this field unless the host controller is in the Halted state
(i.e. HCHalted in the USBSTS register is a one).
1
When set to a 1, the Host Controller proceeds with the execution of
the schedule. The Host Controller continues execution as long as this
bit is set to a one.