STOP PROCESSING STATE
MOTOROLA
PROCESSING STATES
7 - 39
Figure 7-18 shows the system being restarted by asserting the IRQA signal. If the exit
from stop state was caused by a low level on the IRQA pin, then the processor will ser-
vice the highest priority pending interrupt. If no interrupt is pending, then the processor
resumes at the instruction following the STOP instruction that brought the processor into
the stop state.
An IRQA deasserted before the end of the stop cycle count will not be recognized as
pending. If IRQA is asserted when the stop cycle count completes, then an IRQA inter-
rupt will be recognized as pending and will be arbitrated with any other interrupts.
Specifically, when IRQA is asserted, the internal clock generator is started and begins a
delay determined by the SD bit of the OMR. When the chip uses the internal clock oscil-
lator, the SD bit should be set to zero, to allow a longer delay time of 128K T cycles
(131,072 T cycles) so that the clock oscillator may stabilize. When the chip uses a stable
external clock, the SD bit may be set to one to allow a shorter (16 T cycle) delay time and
a faster start up of the chip.
For example, assume that SD=0 so that the 128K T counter is used. During the 128K T
count, the processor ignores interrupts until the last few counts and, at that time, begins
to synchronize them. At the end of the 128K T cycle delay period, the chip restarts
instruction processing, completes stop cycle 4 (interrupt arbitration occurs at this time),
and executes stop cycles 5, 6, 7, and 8 (it takes 17T from the end of the 128K T delay to
FETCH
n3
n4
—
—
ii1
DECODE
n2
STOP
—
—
EXECUTE
n1
n2
STOP
—
STOP CYCLE COUNT
1
2
3
4
5
6
7
8
(9)
IRQA
= INTERRUPT REQUEST A SIGNAL
n = NORMAL INSTRUCTION WORD
STOP = INTERRUPT INSTRUCTION WORD
RESUME STOP CYCLE COUNT 4,
INTERRUPTS ENABLED
IRQA
CLOCK STOPPED
131,072 T OR 16 T CYCLE COUNT STARTED
Figure 7-18 STOP Instruction Sequence Followed by IRQA
Summary of Contents for DSP56K
Page 12: ...xii LIST of TABLES MOTOROLA List of Tables Continued Table Page Number Title Number ...
Page 13: ...MOTOROLA DSP56K FAMILY INTRODUCTION 1 1 SECTION 1 DSP56K FAMILY INTRODUCTION ...
Page 31: ...MOTOROLA DATA ARITHMETIC LOGIC UNIT 3 1 SECTION 3 DATA ARITHMETIC LOGIC UNIT ...
Page 50: ...DATA ALU SUMMARY 3 20 DATA ARITHMETIC LOGIC UNIT MOTOROLA ...
Page 51: ...MOTOROLA ADDRESS GENERATION UNIT 4 1 SECTION 4 ADDRESS GENERATION UNIT ...
Page 77: ...MOTOROLA PROGRAM CONTROL UNIT 5 1 SECTION 5 PROGRAM CONTROL UNIT ...
Page 124: ...INSTRUCTION GROUPS 6 30 INSTRUCTION SET INTRODUCTION MOTOROLA ...
Page 125: ...MOTOROLA PROCESSING STATES 7 1 SECTION 7 PROCESSING STATES STOP WAIT EXCEPTION NORMAL RESET ...
Page 167: ...STOP PROCESSING STATE MOTOROLA PROCESSING STATES 7 43 ...
Page 168: ...STOP PROCESSING STATE 7 44 PROCESSING STATES MOTOROLA ...
Page 169: ...MOTOROLA PORT A 8 1 SECTION 8 PORT A ...
Page 176: ...PORT A INTERFACE 8 8 PORT A MOTOROLA ...
Page 177: ...MOTOROLA PLL CLOCK OSCILLATOR 9 1 SECTION 9 PLL CLOCK OSCILLATOR x x d Φ VCO ...
Page 191: ...10 2 ON CHIP EMULATION OnCE MOTOROLA SECTION 10 ON CHIP EMULATION OnCE ...
Page 218: ...USING THE OnCE MOTOROLA ON CHIP EMULATION OnCE 10 29 ...
Page 604: ...INSTRUCTION ENCODING A 338 INSTRUCTION SET DETAILS MOTOROLA ...
Page 605: ...MOTOROLA BENCHMARK PROGRAMS B 1 APPENDIX B BENCHMARK PROGRAMS T T T T T P1 P3 P2 P4 T T T ...
Page 609: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 5 ...
Page 611: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 7 ...
Page 613: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 9 ...
Page 615: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 11 ...