Functional Description
21-8
ADSP-214xx SHARC Processor Hardware Reference
The TWI controller’s clock output follows these rules:
• Once the clock high (
CLKHI
) count is complete, the serial clock out-
put is driven low and the clock low (
CLKLOW
) count begins.
• Once the clock low count is complete, the serial clock line is
three-stated and the clock synchronization logic enters into a delay
mode (shaded area) until the
TWI_CLOCK
line is detected at a logic 1
level. At this time, the clock high count begins.
The TWI controller only issues a clock during master mode operation and
only at the time a transfer has been initiated. If arbitration for the bus is
lost, the serial clock output immediately three-states. If multiple clocks
attempt to drive the serial clock line, the TWI controller synchronizes its
clock with the other remaining clocks. This is illustrated in
The TWI controller follows the transfer protocol of the
Philips I
2
C Bus
Specification version 2.1
dated January 2000. A simple complete transfer is
diagrammed in
Figure 21-2. TWI Clock Synchronization
HIGH
COUNT
LOW
COUNT
TWI CONTROLLER
CLOCK
SECOND MASTER
CLOCK
TWI_CLOCK
RESULT
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Содержание SHARC ADSP-214 Series
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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...