Motorola DSP96002 - Manual (Page 492)

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STOP Stop Instruction Processing STOP
00 0000 0000 1111
31 14 13 0
0000 0000 0000 0000 00
Instruction Fields:
None
Timing: n/a
Memory: 1 program words
Operation:
Enter the STOP processing state and
stop the clock oscillator.
Assembler Syntax:
STOP
Description:
When a STOP instruction is executed, the processor enters the STOP processing state. The clock oscil-
lator is gated off. All activity in the processor is suspended until the
—
R
—
E
—
S
—
E
–
T or
—
I
—
R
—
Q
–
A pin
is asserted. The STOP processing state is the lowest-power stand-by state.
During the STOP state, port A is in an idle state with the control signals held inactive (i.e.,
—
R
–
D =
—
W
–
R
= V
cc
etc., the data pins (D0–D23) are high impedance, and the address pins (A1–A15) are unchanged from
the previous instruction. If the bus grant was asserted when the STOP instruction was executed, port A will
remain three-stated until the DSP exits the STOP state.
If the exit from the STOP state was caused by a low level on the
—
R
—
E
—
S
—
E
–
T pin, then the processor
will enter the reset processing state. Consult the DSP96002 Technical Data Sheet (DSP96002/D) for timing
details.
If the exit from the STOP state was caused by a low level on the
—
I
—
R
—
Q
–
A pin, then the processor will
service the highest priority pending interrupt and will not service the
—
I
—
R
—
Q
–
A interrupt unless it is high-
est priority. The interrupt will be serviced after an internal delay (see the DSP96002 Technical Data Sheet
(DSP96002/D) for details). The processor will resume program execution at the instruction following the
STOP instruction that caused the entry into the STOP state after the interrupt has been serviced or if no
interrupt was pending immediately after the delay. If the
—
I
—
R
—
Q
–
A pin is asserted when the STOP in-
struction is executed, the clock will not be gated off, and the internal delay counter will be started.
CCR Condition Codes: Not affected.
ER Status Bits: Not affected.
IER Flags: Not affected.
Instruction Format: STOP