STOP

STOP Stop Instruction Processing (AGU)

Operation

Assembler Syntax

Enter the stop processing state.

STOP

STOP

Description

STOP

Halts instruction execution and enters the STOP processing state. This state is intended for the lowest power consumption mode. The core informs the system about the intention to enter the STOP processing state, and it is up to the system to shut down the clocks.

All activity in the processor is halted until one of the following actions occurs:

The wake_from_stop signal is asserted. In many chip configurations, this core interface signal is connected to one of the external interrupt request pins.

A low level is applied to the RESET_B signal.

A low level is applied to the EE0 debug signal.

A JTAG debug request command is made.

Any of these actions causes the core to exit the STOP processing state, as follows:

If STOP is exited by assertion of the RESET signal, the processor enters the reset processing state.

If STOP is exited in parallel with an external interrupt request, the processor services the highest priority pending interrupt. If no interrupt is pending, or if no interrupt is enabled, the processor resumes execution at the instruction following the STOP instruction that caused entry into the stop state.

If STOP is exited by a low level on the EE0 signal or a JTAG debug request command, the processor enters the debug state immediately.

Status and Conditions that Affect Instruction

Register Address

Bit Name

Description

SR[18]

EXP

Determines execution working mode.

Status and Conditions Changed by Instruction

None

Instruction Formats and Opcodes

Instruction

Words

Cycles

Type

STOP

1

8

4

Opcode

15

8

7

0

1 0 0 1 1 1 1 1 0 1 1 1 1 0 0 1

A-388

SC140 DSP Core Reference Manual

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Freescale Semiconductor SC140 Stop Stop Instruction Processing AGU Operation, Enter the stop processing state