first commit
This commit is contained in:
Jérôme Delacotte
372
ATMEGA_SLEEP/ATMEGA_SLEEP.ino
Executable file
372
ATMEGA_SLEEP/ATMEGA_SLEEP.ino
Executable file
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/*
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6-13-2011
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Low Power Testing
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Spark Fun Electronics 2011
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Nathan Seidle
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This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
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This code is written to control a 7 segment display with as little power as possible, waking up only
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when the external button is hit or when the 32kHz oscillator rolls over every 8 seconds.
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Make sure to turn off Brown out detect (uses ~16uA).
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6-23-2011: Down to 38uA!
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6-29-2011: 17uA, not sure why.
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7-2-2011: Currently (hah!) at 1.13uA
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7-4-2011: Let's wake up every 8 seconds instead of every 1 to save even more power
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Since we don't display seconds, this should be fine
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Let's reduce the system clock to 8MHz/256 so that when servicing Timer2 int, we run even lower
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We are now at ~1.05uA on average
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*/
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#include <avr/sleep.h> //Needed for sleep_mode
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#include <avr/power.h> //Needed for powering down perihperals such as the ADC/TWI and Timers
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#define TRUE 1
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#define FALSE 0
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int show_the_time = FALSE;
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//For testing
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long seconds = 2317;
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int minutes = 58;
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int hours = 12;
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int digit1 = 11; //PWM, Display pin 1
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int digit2 = 10; //PWM, Display pin 2
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int digit3 = 9; //PWM, Display pin 6
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int digit4 = 6; //PWM, Display pin 8
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int segA = A1; //Display pin 14
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int segB = 3; //Display pin 16
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int segC = 4; //Display pin 13
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int segD = 5; //Display pin 3
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int segE = A0; //Display pin 5
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int segF = 7; //Display pin 11
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int segG = 8; //Display pin 15
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//The very important 32.686kHz interrupt handler
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SIGNAL(TIMER2_OVF_vect){
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//seconds++;
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seconds += 8; //We sleep for 8 seconds instead of 1 to save more power
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//We don't update minutes and hours here to save power
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//Instead, we update the minutes and hours when you hit the display button
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}
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//The interrupt occurs when you push the button
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SIGNAL(INT0_vect){
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//When you hit the button, we will need to display the time
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if(show_the_time == FALSE) show_the_time = TRUE;
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}
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void setup() {
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//To reduce power, setup all pins as inputs with no pullups
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for(int x = 1 ; x < 18 ; x++){
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pinMode(x, INPUT);
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digitalWrite(x, LOW);
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}
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pinMode(2, INPUT); //This is the main button, tied to INT0
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digitalWrite(2, HIGH); //Enable internal pull up on button
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//These pins are used to control the display
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pinMode(segA, OUTPUT);
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pinMode(segB, OUTPUT);
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pinMode(segC, OUTPUT);
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pinMode(segD, OUTPUT);
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pinMode(segE, OUTPUT);
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pinMode(segF, OUTPUT);
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pinMode(segG, OUTPUT);
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//These are PWM pins
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pinMode(digit1, OUTPUT);
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pinMode(digit2, OUTPUT);
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pinMode(digit3, OUTPUT);
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pinMode(digit4, OUTPUT);
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//Power down various bits of hardware to lower power usage
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set_sleep_mode(SLEEP_MODE_PWR_SAVE);
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sleep_enable();
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//Shut off ADC, TWI, SPI, Timer0, Timer1
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ADCSRA &= ~(1<<ADEN); //Disable ADC
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ACSR = (1<<ACD); //Disable the analog comparator
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DIDR0 = 0x3F; //Disable digital input buffers on all ADC0-ADC5 pins
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DIDR1 = (1<<AIN1D)|(1<<AIN0D); //Disable digital input buffer on AIN1/0
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power_twi_disable();
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power_spi_disable();
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power_usart0_disable();
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power_timer0_disable(); //Needed for delay_ms
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power_timer1_disable();
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//power_timer2_disable(); //Needed for asynchronous 32kHz operation
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//Setup TIMER2
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TCCR2A = 0x00;
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//TCCR2B = (1<<CS22)|(1<<CS20); //Set CLK/128 or overflow interrupt every 1s
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TCCR2B = (1<<CS22)|(1<<CS21)|(1<<CS20); //Set CLK/1024 or overflow interrupt every 8s
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ASSR = (1<<AS2); //Enable asynchronous operation
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TIMSK2 = (1<<TOIE2); //Enable the timer 2 interrupt
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//Setup external INT0 interrupt
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EICRA = (1<<ISC01); //Interrupt on falling edge
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EIMSK = (1<<INT0); //Enable INT0 interrupt
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//System clock futzing
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//CLKPR = (1<<CLKPCE); //Enable clock writing
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//CLKPR = (1<<CLKPS3); //Divid the system clock by 256
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//Serial.begin(9600);
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//Serial.println("32kHz Testing:");
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sei(); //Enable global interrupts
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}
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void loop() {
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sleep_mode(); //Stop everything and go to sleep. Wake up if the Timer2 buffer overflows or if you hit the button
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if(show_the_time == TRUE) {
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//Update the minutes and hours variables
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minutes += seconds / 60; //Example: seconds = 2317, minutes = 58 + 38 = 96
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seconds %= 60; //seconds = 37
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hours += minutes / 60; //12 + (96 / 60) = 13
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minutes %= 60; //minutes = 36
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//Here is where we assume 12 hour display
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while(hours > 12)
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hours -= 12;
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//while(hours > 24) hours -= 24;
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/*Serial.print(hours, DEC);
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Serial.print(":");
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Serial.print(minutes, DEC);
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Serial.print(":");
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Serial.println(seconds, DEC);*/
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for(int x = 0 ; x < 500 ; x++)
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displayNumber(1234);
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digitalWrite(A5, HIGH);
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fake_msdelay(100); //Small debounce
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digitalWrite(A5, LOW);
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show_the_time = FALSE;
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}
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}
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//This is a not-so-accurate delay routine
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//Calling fake_msdelay(100) will delay for about 100ms
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//Assumes 8MHz clock
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void fake_msdelay(int x){
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for( ; x > 0 ; x--)
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fake_usdelay(1000);
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}
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//This is a not-so-accurate delay routine
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//Calling fake_usdelay(100) will delay for about 100us
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//Assumes 8MHz clock
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void fake_usdelay(int x){
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for( ; x > 0 ; x--) {
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__asm__("nop\n\t");
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__asm__("nop\n\t");
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__asm__("nop\n\t");
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__asm__("nop\n\t");
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__asm__("nop\n\t");
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__asm__("nop\n\t");
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__asm__("nop\n\t");
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}
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}
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//Given a number, we display 10:22
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//After running through the 4 numbers, the display is left turned off
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void displayNumber(int toDisplay) {
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#define DISPLAY_BRIGHTNESS 500
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//Display brightness
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//Each digit is on for a certain amount of microseconds
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//Then it is off until we have reached a total of 20ms for the function call
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//Let's assume each digit is on for 1000us
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//If each digit is on for 1ms, there are 4 digits, so the display is off for 16ms.
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//That's a ratio of 1ms to 16ms or 6.25% on time (PWM).
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//Let's define a variable called brightness that varies from:
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//5000 blindingly bright (15.7mA current draw per digit)
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//2000 shockingly bright (11.4mA current draw per digit)
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//1000 pretty bright (5.9mA)
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//500 normal (3mA)
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//200 dim but readable (1.4mA)
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//50 dim but readable (0.56mA)
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//5 dim but readable (0.31mA)
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//1 dim but readable in dark (0.28mA)
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#define DIGIT_ON HIGH
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#define DIGIT_OFF LOW
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//long beginTime = millis();
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for(int digit = 4 ; digit > 0 ; digit--) {
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//Turn on a digit for a short amount of time
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switch(digit) {
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case 1:
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digitalWrite(digit1, DIGIT_ON);
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break;
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case 2:
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digitalWrite(digit2, DIGIT_ON);
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break;
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case 3:
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digitalWrite(digit3, DIGIT_ON);
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break;
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case 4:
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digitalWrite(digit4, DIGIT_ON);
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break;
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}
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//Turn on the right segments for this digit
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lightNumber(toDisplay % 10);
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toDisplay /= 10;
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//delayMicroseconds(DISPLAY_BRIGHTNESS); //Display this digit for a fraction of a second (between 1us and 5000us, 500 is pretty good)
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fake_usdelay(1500); //Display this digit for a fraction of a second (between 1us and 5000us, 500 is pretty good)
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//Turn off all segments
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lightNumber(10);
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//Turn off all digits
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digitalWrite(digit1, DIGIT_OFF);
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digitalWrite(digit2, DIGIT_OFF);
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digitalWrite(digit3, DIGIT_OFF);
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digitalWrite(digit4, DIGIT_OFF);
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}
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//while( (millis() - beginTime) < 10) ; //Wait for 20ms to pass before we paint the display again
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fake_msdelay(1);
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}
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//Given a number, turns on those segments
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//If number == 10, then turn off number
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void lightNumber(int numberToDisplay) {
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#define SEGMENT_ON LOW
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#define SEGMENT_OFF HIGH
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switch (numberToDisplay){
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case 0:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_ON);
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digitalWrite(segF, SEGMENT_ON);
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digitalWrite(segG, SEGMENT_OFF);
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break;
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case 1:
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digitalWrite(segA, SEGMENT_OFF);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_OFF);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_OFF);
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digitalWrite(segG, SEGMENT_OFF);
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break;
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case 2:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_OFF);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_ON);
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digitalWrite(segF, SEGMENT_OFF);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 3:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_OFF);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 4:
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digitalWrite(segA, SEGMENT_OFF);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_OFF);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_ON);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 5:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_OFF);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_ON);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 6:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_OFF);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_ON);
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digitalWrite(segF, SEGMENT_ON);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 7:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_OFF);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_OFF);
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digitalWrite(segG, SEGMENT_OFF);
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break;
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case 8:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_ON);
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digitalWrite(segF, SEGMENT_ON);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 9:
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digitalWrite(segA, SEGMENT_ON);
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digitalWrite(segB, SEGMENT_ON);
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digitalWrite(segC, SEGMENT_ON);
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digitalWrite(segD, SEGMENT_ON);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_ON);
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digitalWrite(segG, SEGMENT_ON);
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break;
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case 10:
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digitalWrite(segA, SEGMENT_OFF);
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digitalWrite(segB, SEGMENT_OFF);
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digitalWrite(segC, SEGMENT_OFF);
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digitalWrite(segD, SEGMENT_OFF);
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digitalWrite(segE, SEGMENT_OFF);
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digitalWrite(segF, SEGMENT_OFF);
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digitalWrite(segG, SEGMENT_OFF);
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break;
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}
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}
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