Fujitsu MB91191 Manuel D’Utilisation

70

CHAPTER 3  CPU

■

Stop status indicates the status that stops all internal clocks and oscillation circuit operation. It can be

minimized the power consumption. 

Transition to the stop status is performed as follow. 

•

Writing in standby control register (STCR) using the instruction

Returning from the stop status is performed one of the following.

•

Interrupt request (only applies to peripherals where interrupt request can be generated even under stop

status)

•

Applying the L level to the RST pin 

Under stop status, all internal clocks are stopped, so built-in peripherals other than those that can generate

interrupts for returning will be stopped.

■

Figure 3.12-9 shows the block diagram of stop control section.

STOP

Internal bus clock

Internal bus

Internal Interrupt

CPU Hold Enable

CPU Hold Request

STOP state display singal

Internal reset

Internal clock generation circuit

State decoder

State transition control circuit

Clock
generation

Internal 
bus clock
generation

Internal 
peripheral
clock
generation

Internal peripheral clock

Clok stop
request singal

Clok cancel
request singal

STOP state transition request signal

Stop signal

Clear

STCR

CPU clock