ST7LITE25F2 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

ST7LITE25F2

8-bit microcontroller with single voltage Flash memory, data EEPROM, ADC, Timers, SPI

STMicroelectronics 

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Power saving modes

9

Power saving modes

ST7LITE20F2 ST7LITE25F2 ST7LITE29F2

9.1

Introduction

To give a large measure of flexibility to the application in terms of power consumption, five

main power saving modes are implemented in the ST7 (see Figure 21):

● Slow

● Wait (and Slow-Wait)

● Active Halt

● Auto Wake up From Halt (AWUF)

● Halt

After a RESET the normal operating mode is selected by default (Run mode). This mode

drives the device (CPU and embedded peripherals) by means of a master clock which is

based on the main oscillator frequency divided or multiplied by 2 (fOSC2).

From RUN mode, the different power saving modes may be selected by setting the relevant

register bits or by calling the specific ST7 software instruction whose action depends on the

oscillator status.

Figure 21. Power saving mode transitions

HIGH

RUN

SLOW

WAIT

SLOW-WAIT

ACTIVE-HALT

AUTO-WAKEUP FROM HALT

HALT

LOW

POWER CONSUMPTION

9.2

SLOW mode

This mode has two targets:

● To reduce power consumption by decreasing the internal clock in the device,

● To adapt the internal clock frequency (fCPU) to the available supply voltage.

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Doc ID 8349 Rev 5

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