ADSP-2126x SHARC Processor Hardware Reference
3-55
Program Sequencer
Latching Interrupts
When the DSP recognizes an interrupt, the DSP’s interrupt latch (
IRPTL
and
LIRPTL
) registers set a bit (latch) to record that the interrupt occurred.
The bits in these registers indicate all interrupts that are currently being
serviced or are pending. Because these registers are readable and writable,
any interrupt except reset (
RSTI
) and emulator (
EMUI
) can be set or cleared
in software.
When an interrupt occurs, the sequencer sets the corresponding bit in
IRPTL
or
LIRPTL
once that interrupt is serviced. Throughout the execution
of the interrupt’s service routine, the DSP clears this bit during every
cycle. This prevents the same interrupt from being latched while its service
routine is executing. After the return from interrupt (
RTI
), the sequencer
stops clearing the latch bit.
If necessary, an interrupt can be reused while it is being serviced. (This is a
matter of disabling this automatic clearing of the latch bit.)
information, see “Reusing Interrupts” on page 3-60.
The interrupt latch bits in
IRPTL
correspond to interrupt mask bits in the
IMASK
register. In both registers, the interrupt bits are arranged in order of
priority. The interrupt priority is from 0 (highest) to 31 (lowest). Inter-
rupt priority determines which interrupt is serviced first when more than
one occurs in the same cycle. Priority also determines which interrupts are
nested when the DSP has interrupt nesting enabled.
tion, see “Nesting Interrupts” on page 3-58.
While the
IRPTL
register latches interrupts for a variety of events, the
LIRPTL
register contains latch and mask bits for the
SP0
,
SP2
,
SP4
,
PP
,
GPT-
MR1
,
GPTMR2
,
DAI
(low priority),
SPI
(low priority) interrupts.
Several events can cause arithmetic interrupts. They are fixed-point over-
flow (
FIXI
) and floating-point overflow (
FLTOI
), underflow (
FLTUI
), and
invalid operation (
FLTII
). To determine which event caused the interrupt,
a program can read the arithmetic status flags in the
STKYx
or
STKYy
status
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...