~toykeeper/flashlight-firmware/anduril2

//v0 5/1/2014 by Everett

        //initial version

        //simple flashlight controller. mode change on power cycle

        

 

#include <htc.h>

#include <pic10f322.h>

#define _XTAL_FREQ 8000000

__CONFIG(CP_OFF & BOREN_OFF & LVP_OFF  & MCLRE_ON & WDTE_OFF & PWRTE_OFF & FOSC_INTOSC & WRT_HALF);

 

#define pwm PWM1DCH

 

persistent unsigned char mode;  //must be declared persistent for ram retention trick to work

enum mode{

        max=0,

        med=1,

        low=2,

};

#define max_mode 2

#define default_mode 0

 

persistent unsigned int key;

unsigned int v_timer; 

bit v_sample;

#define voltage_rate 100 //milliseconds

 

void delayms(int milliseconds);

void configure(void);

unsigned char read_voltage(void);

void initialize_mode(void);

 

void interrupt isr(void)

{

 

        if(TMR0IF){     //fires at 1kHz

                TMR0IF=0;

                if(++v_timer==voltage_rate){v_timer=0; v_sample=1;}

        }

}

 

 

void main(void)

{

        configure();    //set up hardware peripherals

        delayms(15);    //short delay to avoid power glitches incrementing mode

        if(key==12345){         //RAM retention trick to detect quick power cycles

                mode++;                 //go to next mode

                if(mode>max_mode){mode=0;}

        }       

        else{                   //long power loss. default to first mode

                mode=default_mode;

                key=12345;

        }               

 

        initialize_mode();      

        GIE=1;  //turn on interrupts

 

        while(1){

                

                if(v_sample){

                        v_sample=0;

                        if(mode==max){                          //if battery goes below 3.0V in max mode, force down to medium mode

                                if(read_voltage()>87){

                                        mode=med;

                                        initialize_mode();

                                }

                        }

                }                       

                

        }       

}

 

void initialize_mode(void)

{

                switch(mode){   //initialize current mode

                default:

                case max:

                        pwm=255;

                        break;

                case med:

                        pwm=25;

                        break;

                case low:

                        pwm=1;

                        break;

        }       

}       

 

unsigned char read_voltage(void)        

{

//fvr is at 1.024V. ADRES = 1.024/Vin*255. Vin = 1.024/(ADRES/255). voltage limit set to 3.0V -> 87. values below this correspond to voltage above 3.0V

        GO_nDONE=1;

        while(GO_nDONE);

        return ADRES;

}

 

        

void delayms(int milliseconds)

{

        while(milliseconds!=0){ __delay_ms(1); milliseconds--;}

}

 

void configure(void)

{

        INTCON=0b00100000;      //tmr0 only

 

        T2CON=0b00000100; //on, no prescale

        PR2=255; 

        TMR2=0;

                

        LATA=0;

        TRISA=0b11111110;       //GP0 output

        ANSELA=0b11110000;      //

        WPUA=0b11111110;

 

        OSCCON=0b01100000;      //8MHz

 

        OPTION_REG=0b00000010;  //8 prescale for 1ms interrupts

 

        FVRCON=0b10000001;      //1.024v to adc

        ADCON=0b10111101;       // fvr

 

        PWM1DCH=0;

        PWM1CON=0b11000000;     //on, output

}