References
14-62
ADSP-BF535 Blackfin Processor Hardware Reference
Suspend/Resume Considerations
During the time that the USB is suspended (
USBD_SUSPEND
output active),
the system may stop all clocks to the USBD module. If the USB device is
powered by the bus, it may be required to stop all clocks to meet the cur-
rent requirements during the suspended state.
On the inactive edge of
USBD_SUSPEND
, the module must immediately
restart its clocks and guarantee stability within 10 ms (USB specification,
section 9.2.6.2).
Note: The 10 ms window is cited in the USB specification and is
supposedly guaranteed by the system software on the USB host.
Because no USB compliance tests exist for USB hosts, the 10 ms
window cannot be guaranteed across all operating system/BIOS
combinations. The system designer is urged to restart the clocks as
quickly as possible.
More information about USB power distribution is given in Chapter 7 of
the USB specification.
References
These reference materials may be of interest to the system integrator:
•
Universal Serial Bus System Architecture
, Don Anderson, Mindshare
Inc.
•
Universal Serial Bus Specification
, Rev 1.1, USB Implementers
Forum, www.usb.org. Available online.
•
Open Host Controller Interface Specification
, Rev 1.0, USB Imple-
menters Forum, www.usb.org. Available online.
Содержание ADSP-BF535 Blackfin
Страница 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Страница 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 908: ...SDRAM Controller External Bus Interface Unit B 36 ADSP BF535 Blackfin Processor Hardware Reference...