dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 609

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

STOP
Operation:
Enter the stop processing state
Description: Enter the stop processing state. All activity in the processor is suspended until the RESET pin is as-
Restrictions:
Example:
Explanation of Example:
Condition Codes Affected:
Instruction Fields:
Instruction Opcodes:
Timing:
Memory:
Freescale Semiconductor
STOP
Operation
STOP
serted, a hardware interrupt signal is asserted, or an on-chip peripheral asserts a signal to exit the stop
processing state. The stop processing state is a very low-power standby mode where all clocks to the
DSC core and interrupt controller (as well as the clocks to many of the on-chip peripherals, such as
serial ports) are gated off. It is still possible for timers to continue to run in the stop state. In these cases
the timers can be individually powered down at the peripheral itself for lower power consumption. The
clock oscillator can also be disabled for lowest power consumption.
When the exit from the stop state is caused by a low level on the RESET pin, the processor enters the
reset processing state. The time to recover from the stop state using RESET depends on a clock stabi-
lization delay that is controlled by the stop delay (SD) bit in the OMR.
When the exit from the stop state is caused by a hardware interrupt request, the processor enters the
exception processing state. The processor services the highest-priority pending interrupt, which may
or may not be the same interrupt that awakened the processor from stop mode. Refer to Section 9.5,
“Stop Processing State,” on page 9-12 for details on the stop mode.
A STOP instruction cannot be repeated using the REP instruction.
A STOP instruction cannot be the last instruction in a DO loop (that is, at the LA).
STOP
As described in the “Description,” the STOP instruction suspends all processor activity until the pro-
cessor is reset or interrupted. The STOP instruction puts the processor in a low-power standby mode.
No new instructions are fetched until the processor exits the STOP processing state.
The condition codes are not affected by this instruction.
Dependent upon chip implementation
1 program word
Operands
; enter low-power standby mode
Stop Instruction Processing
Dependent upon chip implementation
15
1
Instruction Set Details
1
1
Assembler Syntax:
STOP
C
12
0
11
0
1
1
1
8
W
1
7
0
Enter STOP low-power mode
0
0
Comments
1
4
1
3
STOP
1
0
A-265
0
0