ST72631K4D1 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST72631K4D1

LOW SPEED USB 8-BIT MCU FAMILY with up to 16K MEMORY, up to 512 BYTES RAM, 8-BIT ADC, WDG, TIMER, SCI & I2C

STMicroelectronics 

ST7263

POWER SAVING MODES (Cont’d)

4.2.3 WAIT mode

WAIT mode places the MCU in a low power con-

sumption mode by stopping the CPU.

This power saving mode is selected by calling the

“WFI” ST7 software instruction.

All peripherals remain active. During WAIT mode,

the I bit of the CC register is forced to 0, to enable

all interrupts. All other registers and memory re-

main unchanged. The MCU remains in WAIT

mode until an interrupt or Reset occurs, whereup-

on the Program Counter branches to the starting

address of the interrupt or Reset service routine.

The MCU will remain in WAIT mode until a Reset

or an Interrupt occurs, causing it to wake up.

Refer to Figure 17.

Figure 17. WAIT Mode Flow Chart

WFI INSTRUCTION

OSCILLATOR

PERIPH. CLOCK

CPU CLOCK

I-BIT

ON

ON

OFF

CLEARED

N

N

INTERRUPT

RESET

Y

Y

OSCILLATOR

ON

PERIPH. CLOCK ON

CPU CLOCK

ON

I-BIT

SET

IF RESET

4096 CPU CLOCK

CYCLES DELAY

FETCH RESET VECTOR

OR SERVICE INTERRUPT

Note: Before servicing an interrupt, the CC register is

pushed on the stack. The I-Bit is set during the inter-

rupt routine and cleared when the CC register is

popped.

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