Reset State
3-10
ADSP-BF535 Blackfin Processor Hardware Reference
Idle state can be entered only in Supervisor mode, and the processor
returns to Supervisor mode when transitioning from the Idle state. Appli-
cation programs in User mode cannot invoke the Idle state, except
through a system call provided by an operating system kernel.
In the following code example, core interrupts are disabled and the
IDLE
instruction is executed. When all the pending processes have completed,
the core disables its clocks. Idle state can be terminated only by asserting a
WAKEUP
signal. For more information, see
“System Interrupt
Wakeup-Enable Register (SIC_IWR)” on page 4-24
. While not required,
an interrupt could also be enabled in conjunction with the
WAKEUP
signal.
When the
WAKEUP
signal is asserted, the processor finishes executing the
SSYNC
instruction. The next instruction in this sequence should be the
STI
. Interrupts are enabled after this instruction is executed.
Example Code for Transition to Idle State
To transition to the Idle state, use code as shown in
Listing 3-3
.
Listing 3-3. Transitioning to Idle State
CLI R0 ; /* disable interrupts */
IDLE ; /* source NOPs into pipeline and assert IDLE output on
SSYNC */
SSYNC ; /* drain the pipeline, IDLE asserts after SSYNC_ACK
back from system */
STI R0 ; /* re-enable interrupts after wakeup */
Reset State
Reset state initializes the processor logic. During Reset state, application
programs and the operating system do not execute.
Содержание ADSP-BF535 Blackfin
Страница 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
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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...
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