ADSP-BF535 Blackfin Processor Hardware Reference
14-47
USB Device
USB host assigns an address to the device and then selects a config-
uration. Optionally, if the
USBD_CFG
interrupt is masked, software
can poll the
USBD_GINTR
register.
7. Read a new USB configuration number from the
USBD_STAT
regis-
ter, or decode and respond to the setup packet (
For more
information, see “Control Transfers” on page 14-11.
).
8. Repeat steps 6 and 7 until a device configuration has been
specified.
9. Program endpoint configuration and interrupt registers according
to the current device configuration.
10.Initialization is complete.
USB Data Transfers
This section documents the programming of the endpoint configuration
registers to support USB data transfers. It includes a number of cases typi-
cally encountered, such as Bulk IN/OUT, Isochronous IN/OUT, and
Control transfers. Exception cases, such as packet retries, bad device
requests, corrupted handshakes, and short transfers, are also discussed.
From the device’s viewpoint, USB Interrupt transfers usually
behave like Bulk transfers. The information that describes Bulk
transfers also applied to USB Interrupt transfers. USB Interrupt
transfers are not discussed separately.
USB Transfer Concepts
In general, the USB does not maintain a transfer count for data transfers
between the device and the host. For isochronous endpoints, the transfer
size is irrelevant, because they get the same bandwidth every frame,
whether they need it or not. Control transfers specify the length of their
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...