
Interrupts and Sequencing
3-52
ADSP-2126x SHARC Processor Hardware Reference
latency associated with the
IRQ2–0
interrupts. If an interrupt is latched by
explicitly writing into the
IRPTL
register, then two instructions are exe-
cuted after that cycle in which
IRPTL
is written.
If nesting is enabled and a higher priority interrupt occurs immediately
after a lower priority interrupt, the service routine of the higher priority
interrupt is delayed by one additional cycle. This delay allows the first
instruction of the lower priority interrupt routine to be executed before it
is interrupted.
For more information, see “Nesting Interrupts” on
Delayed Interrupt Processing
Certain DSP operations that span more than one cycle hold off interrupt
processing. If an interrupt occurs during one of these operations, the DSP
latches the interrupt, but delays its processing. The operations that have
delayed interrupt processing are:
• A branch (
JUMP
or
CALL
/
RETURN
) instruction and the following
cycle, whether it is an instruction (in a delayed branch) or a
NOP
(in
a non-delayed branch)
• The first of the two cycles used to perform a program memory data
access and an instruction fetch (a bus conflict) when the instruc-
tion is not cached
• The third-to-last iteration of a one instruction loop
• The last iteration of either a one instruction loop executed once or
twice or a two instruction loop executed once, and the following
cycle (which is a
NOP
)
• The first of the two cycles used to fetch and decode the first
instruction of an interrupt service routine
• Any wait states for external memory accesses
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 ...