ADSP-BF535 Blackfin Processor Hardware Reference
13-13
PCI Bus Interface
A problem arises on writes because the internal bus protocols employed on
the ADSP-BF535 processor support only byte, half word, and word
transfers. In an effort to avoid the complexity of breaking writes into mul-
tiple transactions, all writes are assumed to have contiguous byte enables
and the number of bits written to is rounded up to the nearest supported
transfer size. This means that attempting to write from PCI to only the
first and third bytes results in writing to the whole word, with possible
corruption of data.
Host Mode Operation
When the ADSP-BF535 processor is in host mode, the core acts as the sys-
tem processor with the PCI interface acting as its host-to-PCI bridge. The
ADSP-BF535 processor is put into host mode by setting the Host/Device
Switch bit in the
PCI_CTL
register. In host mode, the core must perform
PCI configuration on any devices attached to the PCI bus. The core must
also configure the ADSP-BF535 processor PCI configuration space, since
it is not accessible from the PCI bus side in host mode. The programmer
should carefully review the values put into the PCI configuration registers
to be sure that all required functionality is enabled correctly.
Outbound Transactions (ADSP-BF535 Processor as
PCI Initiator)
Outbound transactions in host mode are accomplished by the same
method as in device mode. The only difference is that the ADSP-BF535
processor is responsible for configuring the devices on the PCI bus for cer-
tain memory ranges.
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...