ADSP-BF535 Blackfin Processor Hardware Reference
14-13
USB Device
Suspend Operation
The
USBD_SUSPEND
output is provided on the module interface to put the
USB transceivers into suspend mode. System hardware can also use this
signal to stop and start the module clocks when the USB is suspended.
When the
USBD_SUSPEND
signal asserts, the system can stop all clocks.
On the inactive edge of
USBD_SUSPEND
, the system must restart all
clocks within 10 ms.
USB Suspend mode is selected by the USB host. When the USB host
wants to put a device into the suspended mode, it stops sending traffic to
the device. After 3 ms of inactivity on the bus, the device automatically
drops into a suspended state. After the USB host generates resume signal-
ing on the bus, the device reenters its active state and resumes
communication on the bus.
Clocking
The 4X USB Clock (
USBD_CLK4X
) is nominally 48 MHz +/- 500 ppm for
full-speed operation. The UDC uses this clock internally to drive a clock
recovery circuit and to generate a 12 MHz clock (full-speed operation for
the UDC module).
The rest of the USBD module operates at system clock frequencies.
USB Transceiver
A USB buffer chip, such as the Philips PDI USB P11A, must be added in
order to use the USB device functionality of the ADSP-BF535 processor.
The diagram in
Figure 14-2
shows how to connect a Philips PDI USB
P11A transceiver to the ADSP-BF535 processor.
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...