Asynchronous Memory Interface
18-18
ADSP-BF535 Blackfin Processor Hardware Reference
Asynchronous Writes
Write accesses can only be initiated by the AMC every 5th
SCLK
cycle. If
the setup period plus the access period plus the hold period is less than 5
cycles,
AMS[x]
deasserts between accesses. This is shown in the next two
examples.
Figure 18-7
shows two core-initiated asynchronous write bus cycles to the
same bank, with timing programmed with setup = 1 cycle, write access = 2
cycles, hold = 2 cycles, and transition time = 1 cycle.
The first asynchronous write bus cycle proceeds as:
• At the start of the setup period,
AMS[x]
, the address bus, data buses,
and
ABE[3:0]
become valid.
• At the beginning of the write access period,
AWE
asserts.
• At the beginning of the hold period,
AWE
deasserts.
• After the hold period,
AMS[x]
remains low for the next setup period
of the next access.
The second asynchronous write bus cycle proceeds as:
• At the start of the setup period,
AMS[x]
is still asserted. The address
and data buses, and
ABE[3:0]
become valid.
• At the beginning of the write access period,
AWE
asserts.
• At the beginning of the hold period,
AWE
deasserts.
• After the hold period,
AMS[x]
deasserts.
Figure 18-8
shows two higher-speed asynchronous write bus cycles to the
same bank, with timing programmed with setup = 1 cycle, write access = 2
cycles, hold = 0 cycles, and transition time = 1 cycle.
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...