D17133CS datasheet(182/289 Pages) NEC

182 / 289 page

CHAPTER 15

STANDBY FUNCTIONS

167

15.3 STOP MODE

15.3.1 STOP Mode Setting

Executing the STOP instruction places the system in STOP mode.

Operand b3b2b1b0 of the STOP instruction is the condition for canceling STOP mode.

Table 15-4. STOP Mode Cancellation Condition

Format: STOP b3b2b1b0B

Bit

STOP Mode Cancellation ConditionNote 1

At 1, this bit enables cancellation by IRQ

×××.Note 2, 3

"Fixed to 0"

Notes

1. At STOP 0000B, only the resets (RESET input; power-ON/power-DOWN reset) are valid.

The microcontroller is internally initialized to the state immediately following the resetting when STOP

0000B is executed.

2. It is required that IP

×××=1. Cancellation by IRQTM is not possible.

3. Even if the STOP instruction is executed when IRQ

×××=1, the STOP instruction is ignored (handled

as a NOP instruction) thus failing to place the system in STOP mode.

15.3.2 Start Address after STOP Mode Cancellation

The start address varies depending on the cancellation condition and the interrupt enable condition.

Table 15-5. Start Address After STOP Mode Cancellation

Cancellation Condition

Start Address after Cancellation

ResetNote 1

Address 0

IRQ

×××Note 2

If DI, the start address is the one following the STOP instruction

If EI, the start address is the interrupt vector.

(If more than one IRQ

××× have been set, the start address is the interrupt

vector with highest priority.)

Notes

1. Valid resets include the RESET input and power-ON/power-DOWN resets.

2. It is required that IP

×××=1. Cancellation by IRQTM is not possible.

D17133CS Datasheet(PDF) 182 Page - NEC