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Viewing changes to tterev3/attiny10_starter_code/attiny10-eswitch.c

  • Committer: Selene Scriven
  • Date: 2015-03-20 03:56:13 UTC
  • mto: This revision was merged to the branch mainline in revision 125.
  • Revision ID: ubuntu@toykeeper.net-20150320035613-ukmszeabb5vglddu
minor top-level doc updates

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tterev3/attiny10_starter_code/attiny10-eswitch.c
 
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//v0 5/1/2014 by Everett
 
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        //initial version
 
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        //simple flashlight controller. mode change on power cycle
 
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//v1 5/3/2014 by Everett
 
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        //adapted to momentary switch
 
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//v2 5/6/2014 by Everett
 
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        //ported to Attiny10 device
 
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#define F_CPU 1000000
 
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#define pwm OCR0BL
 
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#define pwm_invert
 
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#include <avr/io.h>
 
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#include <avr/interrupt.h>
 
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#include <util/delay.h>
 
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#include <avr/sleep.h>
 
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unsigned char mode;
 
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enum mode{
 
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        max=0,
 
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        med=1,
 
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        low=2,
 
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        off=3,
 
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};
 
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#define max_mode 3
 
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#define default_mode 0
 
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unsigned int v_timer;
 
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char v_sample;
 
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#define voltage_rate 100 //milliseconds
 
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char pressed;
 
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char new_press;
 
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char switch_count;
 
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unsigned char isr_prescale;
 
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void configure(void);
 
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unsigned char read_voltage(void);
 
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void initialize_mode(void);
 
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void debounce(void);
 
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void shutdown(void);
 
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ISR(TIM0_OVF_vect) //fires at 4kHz
 
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{
 
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        isr_prescale++;
 
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        if(isr_prescale>=4){    //prescale since timer only has the 4kHz option
 
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                isr_prescale=0;
 
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                debounce();
 
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                if(++v_timer==voltage_rate){v_timer=0; v_sample=1;}
 
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        }
 
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}
 
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ISR(INT0_vect)
 
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{
 
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        //no action, but ISR must be included since it will execute upon waking
 
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}
 
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int main(void)
 
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{
 
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        configure();    //set up hardware peripherals
 
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        mode=default_mode;
 
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        initialize_mode();
 
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        pressed=0; new_press=0; switch_count=10;
 
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        sei();  //turn on interrupts
 
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        while(1){
 
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                if(v_sample){
 
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                        v_sample=0;
 
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                        if(mode==max){                          //if battery goes below threshold in max mode, force down to medium mode
 
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                                if(read_voltage()<100){ //set threshold for external voltage here
 
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                                        mode=med;
 
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                                        initialize_mode();
 
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                                }
 
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                        }
 
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                }
 
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                if(new_press){
 
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                        new_press=0;
 
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                        mode++;
 
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                        if(mode>max_mode) mode=0;
 
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                        initialize_mode();
 
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                }
 
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                if(mode==off)
 
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                {
 
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                        shutdown();     //shutdown will lock up here until a press wakes the device
 
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                }
 
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        }
 
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}
 
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void shutdown(void)
 
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{
 
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        TIMSK0=0;       //stop timer interrupt
 
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        pwm=0;  //zero output
 
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        TCCR0A=0; //turn off pwm
 
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        #ifdef pwm_invert
 
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        PORTB|=0b00000010;
 
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        #else
 
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        PORTB=0;                //ensure pin is low
 
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        #endif
 
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        ADCSRA=0;       //adc off
 
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        PRR=3;  //power reduce on adc and timer0
 
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        while(1)        //make this a loop so we stay here until sure the switch went down
 
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        {
 
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                do{
 
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                        debounce();
 
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                        _delay_ms((char)1);
 
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                }while(pressed);        //ensure switch is up
 
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                EICRA=0;        //interrupt on low level of int0
 
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                EIMSK=1;        
 
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                SMCR=0b00000101;        //enable sleep
 
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                sleep_cpu();
 
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                EIMSK=0;
 
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                SMCR=0b00000100;        //disable sleep 
 
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                pressed=0; switch_count=10;
 
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                for(char i=0; i<40; i++){       //watch for up to 40ms for a solid press
 
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                        debounce();
 
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                        _delay_ms((char)1);
 
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                        if(pressed) break;      //if pressed break out of for loop
 
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                }
 
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                if(pressed) break;      //if pressed break out of sleep loop
 
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        }
 
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        configure();    //set up hardware for operation
 
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132
}
 
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134
void debounce(void)
 
135
{
 
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        static char port_copy=0xff;
 
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        #define switch_mask 0b00000001  //this selects PB0 as the switch
 
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        if((PINB&switch_mask)==port_copy)       //if the current state matches previous state
 
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        {
 
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                if(--switch_count==0)   //count down samples. if 10 consecutive samples matched
 
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                {
 
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                        switch_count=10;        //reset sample counter
 
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                        if(PINB&switch_mask) pressed=0; //if the state is high, switch is up
 
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                        else            //else switch is down. check for new press
 
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                        {
 
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                                if(pressed==0) new_press=1;     //if last state of pressed was 0, this is a new press
 
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                                pressed=1;      //switch is now down
 
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                        }
 
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                }
 
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        }
 
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        else    //state doesn't match,
 
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        {
 
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                switch_count=10;        //reset sample counter
 
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                port_copy=(PINB&switch_mask);   //get new sample
 
156
        }
 
157
}
 
158
 
 
159
void initialize_mode(void)
 
160
{
 
161
        switch(mode){   //initialize current mode
 
162
                default:
 
163
                case max:
 
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                pwm=255;
 
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                break;
 
166
                case med:
 
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                pwm=25;
 
168
                break;
 
169
                case low:
 
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                pwm=1;
 
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                break;
 
172
                case off:
 
173
                pwm=0;
 
174
                break;
 
175
        }
 
176
}
 
177
 
 
178
unsigned char read_voltage(void)
 
179
{
 
180
        ADCSRA|=(1<<ADSC);      
 
181
        while(ADCSRA&(1<<ADSC));
 
182
        return ADCL;
 
183
}
 
184
 
 
185
 
 
186
void configure(void)
 
187
{
 
188
        PRR=0;
 
189
        TIMSK0=0b00000001;      //interrupt on t0 overflow
 
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        pwm=0;
 
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        #ifdef pwm_invert
 
192
        TCCR0A=0b00110001;      //output B inverted
 
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        #else
 
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        TCCR0A=0b00100001;      //output B on, not inverted, 8bit pwm,
 
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        #endif
 
196
        TCCR0B=0b00001001;      //no prescale for 3906Hz pwm and interrupt
 
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        GTCCR=0;
 
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        PORTB=0;
 
200
        DDRB=0b00000010;        //PB1 output
 
201
        DIDR0=0b00000100;       //PB2 analog
 
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        PUEB=0b11111001;        //pull up switch and reset
 
203
 
 
204
        ADMUX=2;        //PB2
 
205
        ADCSRA=0b10000011;      // 
 
206
 
 
207
        SMCR=0b00000100;        //enable power down mode
 
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}