KS57C2308/P2308/C2316/P2316SAM47 INSTRUCTION SET

IDLE — Idle Operation

IDLE

 

 

 

 

 

 

 

 

 

Operation:

Operand

Operation Summary

Bytes

Cycles

 

 

 

 

 

 

Engage CPU idle mode

2

2

 

 

 

 

 

Description: IDLE causes the CPU clock to stop while the system clock continues oscillating by setting bit 2 of the power control register (PCON). After an IDLE instruction has been executed, peripheral hardware remains operative.

In application programs, an IDLE instruction must be immediately followed by at least three NOP instructions. This ensures an adequate time interval for the clock to stabilize before the next instruction is executed. If more than three NOP instructions are not used after IDLE instruction, leakage current could be flown because of the floating state in the internal bus.

Operand

 

 

 

Binary Code

 

 

 

Operation Notation

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1

 

1

1

 

1

1

1

PCON.2 1

 

 

 

 

 

 

 

 

 

 

 

 

 

1

0

1

 

0

0

 

0

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

Example: The instruction sequence

IDLE

NOP

NOP

NOP

sets bit 2 of the PCON register to logic one, stopping the CPU clock. The three NOP instructions provide the necessary timing delay for clock stabilization before the next instruction in the program sequence is executed.

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Samsung KS57C2308 manual Idle Idle Operation, Idle NOP