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ACCURATE TIMEBASE FOR LOW-COST ST7 APPLICATIONS WITH INTERNAL RC...

3 SOFTWARE EXAMPLE

This software example includes all the algorithms. It includes a basic algorithm for finding the

fraction and also contains average and glitch algorithms. It has calibration routines for the

PWM counter and SCI baud rate.

3.1 MAIN PROGRAM

/********************************************************************************

COPYRIGHT 2002 STMicroelectronics

Source File Name: main.c

Group

: IPSW, CMG - IPDF

Author

: MCD Application Team

Date First Issued: 01/07/2002

********************************Documentation**********************************

General Purpose - This routine provides internal RC deviation measurement and

calibration of PWM counter and SCI baud rate.

********************************Revision History********************************

Date: 01/07/2002

Release: 1.0

******************************************************************************/

#include "ST7lib_config.h"

/*Configuration File*/

unsigned char cap;

unsigned int capture1,capture2;

const unsigned char buff1[36]= " SCI CALIBRATION DONE ";

/******************************************************************************

MAIN APPLICATION BEGINS

******************************************************************************/

#define TIMERB_PWM_CAL

#define SCI_CAL

void main (void)

{

/******************************************************************************

Variable declaration for measuring the capture inputs with averaging and

glitch filter algorithm

******************************************************************************/

unsigned char i;

unsigned int capture_range;

float fraction=0.0;

/******************************************************************************

Variable declaration for calibrating PWM w.r.t Internal RC frequency

******************************************************************************/

unsigned int PWM_CNT, PWM_CNT1;

/******************************************************************************

Variable declaration to calibrate SCI baudrate w.r.t Internal RC frequency

******************************************************************************/

unsigned char CALTR;

float CALTR_TEMP = 0.0;

/******************************************************************************

Initialisation of the varibles

******************************************************************************/

cap=capture1=capture2=0;

PWM_CNT = 0; PWM_CNT1 = 0; CALTR =0;

capture_range = 0;