Asynchronous Memory Interface
18-16
ADSP-BF535 Blackfin Processor Hardware Reference
Programmable Timing Characteristics
This section describes the programmable timing characteristics for the
EBIU. Timing relationships depend on the programming of the AMC,
whether initiation is from the core or from MemDMA, and the sequence
of transactions (read followed by read, read followed by write, etc.).
Asynchronous Accesses by Core Instructions
Some external memory accesses are caused by core instructions of the type:
R0 = [P0++] ; /* Read from external memory, where P0 points to
a location in external memory */
or:
[P0++] = R0 ; /* Write to external memory */
Asynchronous Reads
Figure 18-6
shows two core-initiated asynchronous read bus cycles to the
same bank, with timing programmed with setup = 1 cycle, read access = 3
cycles, hold = 2 cycles, and transition time = 1 cycle.
Asynchronous read bus cycles proceed as:
• At the start of the setup period,
AMS[x]
, the address bus, and
ABE[3:0]
become valid, and
AOE
asserts.
• At the beginning of the read access period and after the setup cycle,
ARE
asserts.
• At the beginning of the hold period, read data is sampled on the
rising edge of
CLKOUT
. The
ARE
pin deasserts after this rising edge.
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...