ADSP-214xx SHARC Processor Hardware Reference
15-17
Serial Peripheral Interface Ports
Variable Frame Delay for Slave
When the processor is configured as an SPI slave, the SPI master must
drive an
SPICLK
signal that conforms with
. For exact timing
parameters, please refer to the appropriate product data sheet.
As shown in
SPIDS
lead time (T1), the
SPIDS
lag time
(T2), and the sequential transfer delay time (T3) must always be greater
than or equal to one-half the
SPICLK
period. The minimum time between
successive word transfers (T4) is two
SPICLK
periods. This time period is
measured from the last active edge of
SPICLK
of one word to the first active
edge of
SPICLK
of the next word. This calculation is independent from the
configuration of the SPI (
CPHASE
,
SPIMS
, and so on).
This is shown as:
T4 = 1.5 SPI clock T3
and
T3 = 0.5 SPICLK period for STDC = 0.
T3 = STDC
×
SPICLK period for STDC > 0.
Unlike previous SHARC processors, a variable frame delay is
included to increase SPI timing flexability.
For a master device with
CPHASE
= 0 or
CPHASE
= 1 (with
AUTODS
set to 1 in
the
SPCTL
register), this means that the slave-select output is inactive
(high) for at least one-half the
SPICLK
period. In this case, T1 and T2 are
each always be equal to one-half the
SPICLK
period.
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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...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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...
Страница 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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...