UM10503
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User manual
Rev. 1.3 — 6 July 2012
594 of 1269
NXP Semiconductors
UM10503
Chapter 24: LPC43xx USB1 Host/Device controller
24.6.2.2 Host mode
15
FS2
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.
0x8
R/W
31:24
-
Reserved
0
Table 460. USB Command register in device mode (USBCMD_D - address 0x4000 7140) bit description
…continued
Bit
Symbol
Value
Description
Reset
value
Access
Table 461. USB Command register in host mode (USBCMD_H - address 0x4000 7140) bit description
Bit
Symbol
Value
Description
Reset
value
Access
0
RS
Run/Stop
0
R/W
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.
1
RST
Controller reset.
Software uses this bit to reset the controller. This bit is set to zero by
the Host/Device Controller when the reset process is complete.
Software cannot terminate the reset process early by writing a zero to
this register.
0
R/W
0
This bit is set to zero by hardware when the reset process is
complete.
1
When software writes a one to this bit, the Host Controller resets its
internal pipelines, timers, counters, state machines etc. to their initial
value. Any transaction currently in progress on USB is immediately
terminated. A USB reset is not driven on downstream ports. Software
should not set this bit to a one when the HCHalted bit in the USBSTS
register is a zero. Attempting to reset an actively running host
controller will result in undefined behavior.
2
FS0
Bit 0 of the Frame List Size bits. See
This field specifies the size of the frame list that controls which bits in
the Frame Index Register should be used for the Frame List Current
index. Note that this field is made up from USBCMD bits 15, 3, and 2.
0
3
FS1
Bit 1 of the Frame List Size bits. See
0