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ST72324 QUICK REFERENCE NOTE

devices on your application board and a Beep Out option which generates 3 selectable

frequencies at a 50% duty cycle.

Useful Tips:

Calibrating Peripheral Parameters for Internal RC Oscillator

Peripherals like the Timer, SCI etc. which depend upon time

calculation, can be calibrated by determining the Internal RC accuracy

error.

For more information, refer to:

AN1530: Accurate Timebase for low cost ST7 applications with Internal

RC oscillator

2.3 INTEGRATED FEATURES FOR MORE RELIABILITY

The system integrity module consists of the Low Voltage Detector (LVD) and Auxiliary Voltage

Detector (AVD).

s

LVD secures the power up and power down stages by keeping the MCU in reset state. There

is no need for an external reset generator.

s

AVD generates an interrupt when the voltage crosses the threshold voltage. This interrupt

can be used as an early warning of an imminent LVD reset so software can perform a safe

shut down.

Useful Tips:

Safe Shutdown with AVD Interrupt

Using the AVD interrupt, the application can store the application

context in emulated Data EEPROM before the LVD generates a reset.

For more information, refer to:

AN1502: Emulated Data EEPROM with ST7 HDFlash memory

2.4 NESTED INTERRUPTS

Nested or concurrent interrupt management with:

s

Flexible interrupt priority and level management.

s

Up to 4 software programmable nesting levels.

This allows easy implementation of a priority based interrupt driven architecture. The device

also has 4 vectors for external interrupts which allows for fast and flexible implementation of

external interrupt handling.