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CALIBRATING THE RC OSCILLATOR OF THE ST7FLITE0 MCU USING THE MAINS

4.2.4 Detailed average version software flowchart

CLEAR RAM BYTES

ENABLE INPUT CAPTURE INTERRUPT

(NBOVER, CR)

STORE STARTING VALUE

80H --> VALUE

80H --> RCCR

EDGE

ON LTIC

INPUT

STORE CAPTURED VALUE IN CAPTURE 1.X

ENABLE TIMEBASE INTERRUPT TO

STORE CAPTURED VALUE IN CAPTURE 2.X

DISABLE TIMEBASE AND INPUT CAPTURE

INTERRUPTS

START TO COUNT TIMER OVERFLOWS

EDGE

ON LTIC

INPUT

SUBTRACT VALUE TO RCCR

ADD VALUE TO RCCR

RC OSCILLATOR IS TRIMMED TO 1 MHZ

COMPARE

RESULT WITH

138H

IS THE

DICHOTOMY

FINISHED?

NO

NO

NO

YES

YES

YES

SMALLER

EQUAL OR GREATER

CALCULATION OF:

NBOVER X F9 + 4(CAPTURE2.X - CAPTURE1.X)

RESULT DIVIDED BY 4 TO AVERAGE IT

DIVIDE VALUE BY 2

FOUR

MEASUREMENTS

DONE?

NO

YES