ADSP-2126x SHARC Processor Hardware Reference
3-61
Program Sequencer
Interrupting IDLE
The sequencer supports placing the DSP in
IDLE
—a special instruction
that halts the processor core in a low power state. The halt occurs until
any interrupt is latched, serviced, and then returned from using the
RTI
instruction. When executing an
IDLE
instruction, the sequencer fetches
one more instruction at the current fetch address and then suspends oper-
ation. The DSP’s I/O processor is not affected by the
IDLE
instruction—
DMA transfers to or from internal memory continue uninterrupted. The
processor’s internal clock and timer (if enabled) continue to run during
IDLE
. When an interrupt occurs, the processor responds normally. After
two cycles used to fetch and decode the first instruction of the interrupt
service routine, the processor continues executing instructions normally.
Summary
To manage events, the sequencer’s interrupt controller handles interrupt
processing, determines whether an interrupt is masked, and generates the
appropriate interrupt vector address.
With selective caching, the instruction cache lets the DSP access data in
program memory and fetch an instruction (from the cache) in the same
cycle. The DAG2 data address generator outputs program memory data
addresses.
The sequencer evaluates conditional instructions and loop termination
conditions by using information from the status registers. The loop
address stack and loop counter stack support nested loops. The status
stack stores status registers for implementing nested interrupt routines.
identifies all the functional blocks and their relationship to one
another in detail.
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...