SDRAM Controller (ADSP-2147x/ADSP-2148x)
3-38
ADSP-214xx SHARC Processor Hardware Reference
Data Mask
The SDRAM controller provides one
DQM
pin (
SDDQM
), all SDRAM
DQM
pins could be connected to
SDDQM
pin . The
SDDQM
pin is driven high from
reset deassertion until SDRAM initialization completes, after that it’s
driven low irrespective of whether any accesses occur.
Note that some manufacturer’s require keeping
DQM
high during the
power-up initialization sequence.
Resetting the Controller
Like any other peripheral, the SDRAM controller can be reset by a hard or
a soft reset. A hard reset puts the PLL in bypass mode where the SDRAM
clock runs at a lower frequency.
A soft reset also causes data loss, and programs need to re-initialize
SDRAM before it can be used again.
Running reset (
RESETOUT
pin as an input) does not reset the
SDRAM controller.
Operating Modes
The following sections provide on the operating modes of the SDRAM
interface.
Parallel Connection of SDRAMs
To specify a SDRAM system, multiple possibilities are given based on the
different memory sizes. For a 16-bit I/O capability, the following can
configured.
• 2 x 16-bit/page 512 words
• 4 x 8-bit/page 1k words
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Содержание SHARC ADSP-214 Series
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Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...