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UM10503
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© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
744 of 1441
NXP Semiconductors
UM10503
Chapter 26: LPC43xx/LPC43Sxx USB1 Host/Device controller
26.6.5.2 Host mode
This register is used by the host controller to index the periodic frame list. The register
updates every 125
s (once each micro-frame). Bits[N: 3] are used to select a particular
entry in the Periodic Frame List during periodic schedule execution. The number of bits
used for the index depends on the size of the frame list as set by system software in the
Frame List Size field in the USBCMD register.
This register must be written as a DWord. Byte writes produce undefined results. This
register cannot be written unless the Host Controller is in the 'Halted' state as indicated by
the HCHalted bit in the USBSTS register (host mode). A write to this register while the
Run/Stop bit is set to a one produces undefined results. Writes to this register also affect
the SOF value.
26.6.6 Device address (DEVICEADDR) and Periodic List Base
(PERIODICLISTBASE) registers
26.6.6.1 Device mode
The upper seven bits of this register represent the device address. After any controller
reset or a USB reset, the device address is set to the default address (0). The default
address will match all incoming addresses. Software shall reprogram the address after
receiving a SET_ADDRESS descriptor.
The USBADRA bit is used to accelerate the SET_ADDRESS sequence by allowing the
DCD to preset the USBADR register bits before the status phase of the SET_ADDRESS
descriptor.
Table 538. USB frame index register in host mode (FRINDEX_H - address 0x4000 714C) bit
description
Bit
Symbol
Description
Reset value
Access
2:0
FRINDEX2_0
Current micro frame number
-
R/W
12:3
FRINDEX12_3
Frame list current index for
1024 elements.
-
R/W
31:13
-
Reserved
-
Table 539. Number of bits used for the frame list index
USBCMD
bit 15
USBCMD
bit 3
USBCMD
bit 2
Frame list size
Size of
FRINDEX12_3
bit field
0
0
0
1024 elements (4096 bytes). Default value.
12
0
0
1
512 elements (2048 bytes)
11
0
1
0
256 elements (1024 bytes)
10
0
1
1
128 elements (512 bytes)
9
1
0
0
64 elements (256 bytes)
8
1
0
1
32 elements (128 bytes)
7
1
1
0
16 elements (64 bytes)
6
1
1
1
8 elements (32 bytes)
5