Universal Serial Bus Interface – On-The-Go Module
MCF52277 Reference Manual, Rev. 1
Freescale Semiconductor
20-19
20.3.4.2
USB Status Register (USBSTS)
This register indicates various states of each module and any pending interrupts. This register does not
indicate status resulting from a transaction on the serial bus. Software clears certain bits in this register by
writing a 1 to them.
1
RST
Controller reset. Software uses this bit to reset controller. Controller clears this bit when reset process
completes. Clearing this register does not allow software to terminate the reset process early.
Host mode:
When software sets this bit, the controller resets its internal pipelines, timers, counters, state machines etc.
to their initial value. Any transaction in progress on the USB immediately terminates. A USB reset is not
driven on downstream ports. Software must not set this bit when the USBSTS[HCH] bit is cleared.
Attempting to reset an actively running host controller results in undefined behavior.
Device mode:
When software sets this bit, the controller resets its internal pipelines, timers, counters, state machines, etc.
to their initial value. Setting this bit with the device in the attached state is not recommended because it has
an undefined effect on an attached host. To ensure the device is not in an attached state before initiating a
device controller reset, all primed endpoints must be flushed and the USBCMD[RS] bit must be cleared.
0
RS
Run/Stop.
Host mode:
When set, the controller proceeds with the execution of the schedule. The controller continues execution as
long as this bit is set. When this bit is cleared, the controller completes the current transaction on the USB
and then halts. The USBSTS[HCH] bit indicates when the host controller finishes the transaction and enters
the stopped state. Software must not set this bit unless controller is in halted state (USBSTS[HCH] = 1).
Device mode:
Setting this bit causes the controller to enable a pull-up on DP and initiate an attach event. This control bit is
not directly connected to the pull-up enable, as the pull-up becomes disabled upon transitioning into
high-speed mode. Software must use this bit to prevent an attach event before the USB OTG controller has
properly initialized. Clearing this bit causes a detach event.
Address: 0xFC0B_0144 (USBSTS)
Access: User read/write
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R
0
0
0
0
0
0
TI1
TI0
0
0
0
0
UPI
UAI
0
NAKI
W
w1c
w1c
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
AS
PS
RCL
HCH
0
0
0
SLI
SRI
URI
AAI
SEI
FRI
PCI
UEI
UI
W
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
w1c
Reset
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
Figure 20-17. USB Status Register (USBSTS)
Table 20-19. USBCMD Field Descriptions (continued)
Field
Description
Содержание MCF52277
Страница 1: ...MCF52277 Reference Manual Devices Supported MCF52274 MCF52277 Document Number MCF52277RM Rev 1 04 2008...
Страница 22: ...MCF52277 Reference Manual Rev 1 Freescale Semiconductor xxii...
Страница 32: ...MCF52277 Reference Manual Rev 0 xxxii Freescale Semiconductor...
Страница 60: ...Signal Descriptions MCF52277 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Страница 112: ...Enhanced Multiply Accumulate Unit EMAC MCF52277 Reference Manual Rev 1 4 20 Freescale Semiconductor...
Страница 128: ...Static RAM SRAM MCF52277 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Страница 140: ...Clock Module MCF52277 Reference Manual Rev 1 7 12 Freescale Semiconductor...
Страница 172: ...Chip Configuration Module CCM MCF52277 Reference Manual Rev 1 9 16 Freescale Semiconductor...
Страница 180: ...Serial Boot Facility SBF MCF52277 Reference Manual Rev 1 10 8 Freescale Semiconductor...
Страница 188: ...Reset Controller Module MCF52277 Reference Manual Rev 1 11 8 Freescale Semiconductor...
Страница 210: ...Crossbar Switch XBS MCF52277 Reference Manual Rev 1 13 8 Freescale Semiconductor...
Страница 480: ...Liquid Crystal Display Controller LCDC MCF52277 Reference Manual Rev 1 21 44 Freescale Semiconductor...
Страница 510: ...Touchscreen Controller Analog to Digital Converter MCF52277 Reference Manual Rev 1 22 30 Freescale Semiconductor...
Страница 542: ...FlexCAN MCF52277 Reference Manual Rev 1 23 32 Freescale Semiconductor...
Страница 568: ...Pulse Width Modulation PWM Module MCF52277 Reference Manual Rev 1 24 26 Freescale Semiconductor...
Страница 640: ...Programmable Interrupt Timers PIT0 PIT1 MCF52277 Reference Manual Rev 1 27 8 Freescale Semiconductor...
Страница 690: ...DMA Serial Peripheral Interface DSPI MCF52277 Reference Manual Rev 1 29 40 Freescale Semiconductor...
Страница 724: ...UART Modules MCF52277 Reference Manual Rev 1 30 34 Freescale Semiconductor...
Страница 740: ...I2 C Interface MCF52277 Reference Manual Rev 1 31 16 Freescale Semiconductor...
Страница 790: ...Debug Module MCF52277 Reference Manual Rev 1 32 50 Freescale Semiconductor...