ADSP-BF535 Blackfin Processor Hardware Reference
13-9
PCI Bus Interface
It is important to note that the PCI interface does not support wrapping
bursts. Any access identified as a wrap signals a bus error and sets the
Unsupported EAB Access bit in the
PCI_STAT
register. The interface treats
wrapping bursts as incrementing bursts, but this behavior should not be
relied upon for normal operation.
Since core cache burst transactions are wrapping bursts, all core access to
the PCI module must be cache inhibited. This is accomplished by correct
configuration of the core Cacheability Protection Lookaside Buffers
(CPLBs), which describe the access characteristics of the core memory
map. The data CPLB entry or entries used to describe the PCI memory
and I/O spaces must have the
CPLB_L1_CHBL
bit cleared. Note that core
instruction fetch from PCI space is not supported.
The PCI protocol is incapable of doing a 4-sequential byte burst, or a
2-sequential 16-bit burst. For bursts smaller than 32 bits, the data is
packed into words and bursted to PCI if necessary.
Table 13-2
shows the
PCI transaction produced for each supported burst size.
Table 13-2. Burst Transaction Conversion to PCI
Supported EAB Burst Transaction
Number and Type of PCI Transaction
Produced
4-beat incrementing 8-bit
Single 32-bit word transaction
8-beat incrementing 8-bit
Two 32-bit word bursts
4-beat incrementing 16-bit
Two 32-bit word bursts
8-beat incrementing 16-bit
Four 32-bit word bursts
4-beat incrementing 32-bit
Four 32-bit word bursts
8-beat incrementing 32-bit
Eight 32-bit word bursts
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...