ADSP-2126x SHARC Processor Hardware Reference
3-47
Program Sequencer
When a program enables the timer, the timer starts decrementing the
TCOUNT
register at the end of the next clock cycle. If the timer is subse-
quently disabled, the timer stops decrementing
TCOUNT
after the next clock
cycle as shown in
.
The timer expired event (
TCOUNT
decrements to zero) generates two inter-
rupts,
TMZHI
and
TMZLI
. For information on latching and masking these
interrupts to select timer expired priority, see
.
As with other interrupts, the sequencer needs two cycles to fetch and
decode the first instruction of the timer expired service routine before exe-
cuting the routine. The pipeline execution for the timer interrupt appears
in
.
Programs can read and write the
TPERIOD
and
TCOUNT
registers by using
universal register transfers. Reading the registers does not effect the timer.
Note that an explicit write to
TCOUNT
takes priority over the sequencer’s
Figure 3-5. Timer Enable and Disable
CCLK
Set TIMEN
Timer Active
TIMER
TCOUNT=N
TCOUNT=N
TCOUNT=N-1
CCLK
Clear TIMEN
Timer Inactive
TIMER
TCOUNT=M–1TCOUNT=M–2 TCOUNT=M–2
in MODE2
ENABLE
in MODE2
DISABLE
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 ...