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HOW TO MINIMIZE THE ST7 POWER CONSUMPTION

– Use Wait mode if you need external interrupt capability in low power mode and if peripherals

are to be remain active.

– Configure the OSCRANGE[2:0] option bits for the minimum frequency range. For example,

if you use 8 MHz oscillator frequency, you must select the OSCRANGE[2:0] option bits for

medium speed resonator 4/8 MHz, not for high speed resonator 8/16 MHz.

6 APPENDIX A: ST72F324 STANDARD EXAMPLES

This section provides examples of how to minimise the consumption in a particular ST7 appli-

cation for device ST72F324.( Use ST72F324 datasheet for a reference)

6.1 EXAMPLE 1: STATIC MEASUREMENT

This example provides a static method of measuring the current consumed by the microcon-

troller in different modes and without any I/O activity. The measurement is done using the fol-

lowing configuration.

6.1.1 Measurement Configuration

– All ports have been set as Push-Pull Outputs at low level.

– All other peripherals are in reset configuration.

– After this, MCU is put into different modes by calling different instructions and by setting

some bits (in the MCCSR register).

– In Option Byte, PLL*2 is disabled, CSS is also disabled and LVD is Off.

Figure 1. Hardware Setup

6.1.2 Consumption

The consumption mainly depends on the mode selected and the CPU frequency.

mA

ST72324