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//*****************************************************************************
// File Name    : a2dtest.c
// 
// Title                : example usage of some avr library functions
// Revision             : 1.0
// Notes                :       
// Target MCU   : Atmel AVR series
// Editor Tabs  : 4
// 
// Revision History:
// When                 Who                     Description of change
// -----------  -----------     -----------------------
// 20-Oct-2002  pstang          Created the program
//*****************************************************************************
 
//----- Include Files ---------------------------------------------------------
#include <avr/io.h>             // include I/O definitions (port names, pin names, etc)
#include <avr/interrupt.h>      // include interrupt support
#include <math.h>

#include "global.h"             // include our global settings
#include "uart2.h"              // include uart function library
#include "rprintf.h"    // include printf function library
#include "timer.h"              // include timer function library (timing, PWM, etc)
#include "a2d.h"                // include A/D converter function library

//----- Begin Code ------------------------------------------------------------
#define BUFLEN 64

int main(void)
{
        u16 i,x,y;
        double fi, err, fibuf[BUFLEN];
        s16 fia, erra;
        u16 fib, errb;

        // initialize our libraries
        // initialize the UART (serial port)
        uartInit();
        uartSetBaudRate(0,9600);
        // make all rprintf statements use uart for output
        rprintfInit(uart0SendByte);
        // initialize the timer system
        timerInit();
        // turn on and initialize A/D converter
        a2dInit();      
        // configure a2d port (PORTA) as input
        // so we can receive analog signals
        DDRA = 0x00;
        // make sure pull-up resistors are turned off
        PORTA = 0x00;

        // set the a2d prescaler (clock division ratio)
        // - a lower prescale setting will make the a2d converter go faster
        // - a higher setting will make it go slower but the measurements
        //   will be more accurate
        // - other allowed prescale values can be found in a2d.h
        a2dSetPrescaler(ADC_PRESCALE_DIV128);

        // set the a2d reference
        // - the reference is the voltage against which a2d measurements are made
        // - other allowed reference values can be found in a2d.h
        a2dSetReference(ADC_REFERENCE_AREF);

        // use a2dConvert8bit(channel#) to get an 8bit a2d reading
        // use a2dConvert10bit(channel#) to get a 10bit a2d reading

        while(1)
        {
                fi=0;
                err=0;
                for(i=0; i<BUFLEN; i++)
                { 
                        x = a2dConvert10bit(ADC_CH_ADC0);
                        y = a2dConvert10bit(ADC_CH_ADC1);
                        fibuf[i] = atan2((double)x-511,(double)y-511);          // record computed angles to buffer for post processing
                }
                for(i=0; i<BUFLEN; i++) fi += fibuf[i];         // sum recorded angles

                fi = ((fi/BUFLEN)+PI) * 180.0 / PI;             // average recorded angles and convert product to degrees

                for(i=0; i<BUFLEN; i++) err += (fibuf[i]-fi)*(fibuf[i]-fi);             // sum cubic errors
                err = sqrt(err/(BUFLEN-1))/sqrt(BUFLEN);        // compute average cubic error
                erra = floor(err);
                errb = floor((err - erra)*1000);
                
                fia = floor(fi);
                fib = floor((fi - fia)*1000);

                
                rprintf("fi:%d.%d  +- %d.%d \r\n", fia, fib, erra, errb);
        }
        return 0;
}