7220 datasheet(120/303 Pages) RENESAS

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7220 Group User’s Manual

2.14 Low-power dissipation mode

2.14.2 Wait mode

The wait mode is set by executing the WIT instruction.

In the wait mode, only the internal clock

φ stops with supplying f(XIN) continuously.

In this case, there is no need to create a wait time by timers as in the case of return from the stop mode,

and operation is restarted immediately after return from the wait state.

When reset input or interrupt is accepted, supply of the internal clock

φ is immediately started, and the

device is returned from the wait state. Because the clock f(XIN) is continuously supplied in the wait state,

return by an internal interrupt as a timer, etc. can also be used.

Table 2.14.2 State in wait mode

The following 2 kinds of interrupts can be used to return from the stop mode to the ordinary mode.

INT1 interrupt

INT2 interrupt

INT3 interrupt

Figure 2.14.4 shows a transitions of low-power dissipation mode.

Table 2.14.3 Invalid interrupts in the wait mode

Fig. 2.14.3 Reset input time

2.14.3 Interrupts in low-power dissipation mode

The following 4 kinds of interrupts are invalid in the wait mode. Therefore, 4 interrupts below cannot be

used to return from the wait mode to the ordinary mode.

Oscillation

CPU

Internal clock

I/O ports

Timer, CRT display functions

Operating

Stop

Stop at HIGH level

State where WIT instruction is executed is held.

Operating

State in wait mode

Item

Interrupt source

Reason

Condition

VSYNC interrupt

CRT interrupt

Timer 2 interrupt

Timer 3 interrupt

—

Count source is input from pin P24/TIM2.

Count source is input from pin P23/TIM3.

The interrupt request bit cannot be set.

The count source cannot be supplied.

RESET

XIN

VCC

Execute WIT instruction

Returned by reset input

Wait mode

µs or more

Oscillation stabilizing time

(Note)

Time to hold internal reset state =

approximately 32768 cycles of XIN

input

FUNCTIONAL DESCRIPTION

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