Hardware components | ||||||
 |
| × | 1 | |||
 |
| × | 1 | |||
 |
| × | 1 | |||
| × | 1 | ||||
 |
| × | 1 | |||
 |
| × | 1 | |||
 |
| × | 1 | |||
Tiny-fy the Arduino
Read moreThis is one of my favorite little chips. Runs Arduino code (not all libraries). Has a variant of sizes and for reference the ATtiny 45 is used.
In order to program the AT-tiny (via arduino) please refer to This Link.
VCC is between 2.7 - 5.5V. This is all about keeping the chip in sleep mode where current draw is at 200 µA (or less).
Two modes covered:
- Sleep with Timer Wake
- Sleep with Interrupt Wake
Sleep with timer wake
ArduinoKeeps AT-tiny asleep and wakes up on timer interval. Then goes back to sleep.
#include <avr/sleep.h>
#include <avr/wdt.h>
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif
int pinLed = 0;
int trig = 2;
int heart = 1;
volatile boolean f_wdt = 1;
int counter = 0;
void setup(){
pinMode(pinLed,OUTPUT);
pinMode(heart,OUTPUT);
pinMode(trig,INPUT);
setup_watchdog(8); // approximately 4 seconds sleep
}
void loop(){
if (f_wdt==1) { // wait for timed out watchdog / flag is set when a watchdog timeout occurs
f_wdt=0; // reset flag
if (counter > 192){ //timer to reset approx 15 min
digitalWrite(pinLed,HIGH);
delay(500); // Wait for trigger high until set back to sleep
while(!digitalRead(trig)){delay(500);}
digitalWrite(pinLed,LOW);
counter = 0;
}
// Show heartbeat uncomment to show blink
//digitalWrite(heart,HIGH);
//delay(200);
//digitalWrite(heart,LOW );
pinMode(pinLed,INPUT); // set all used port to intput to save power
system_sleep();
pinMode(pinLed,OUTPUT); // set all ports into state before sleep
}
}
// set system into the sleep state
// system wakes up when wtchdog is timed out
void system_sleep() {
cbi(ADCSRA,ADEN); // switch Analog to Digitalconverter OFF
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
sleep_enable();
sleep_mode(); // System sleeps here
sleep_disable(); // System continues execution here when watchdog timed out
sbi(ADCSRA,ADEN); // switch Analog to Digitalconverter ON
}
// 0=16ms, 1=32ms,2=64ms,3=128ms,4=250ms,5=500ms
// 6=1 sec,7=2 sec, 8=4 sec, 9= 8sec
void setup_watchdog(int ii) {
byte bb;
int ww;
if (ii > 9 ) ii=9;
bb=ii & 7;
if (ii > 7) bb|= (1<<5);
bb|= (1<<WDCE);
ww=bb;
MCUSR &= ~(1<<WDRF);
// start timed sequence
WDTCR |= (1<<WDCE) | (1<<WDE);
// set new watchdog timeout value
WDTCR = bb;
WDTCR |= _BV(WDIE);
}
// Watchdog Interrupt Service / is executed when watchdog timed out
ISR(WDT_vect) {
counter++;
f_wdt=1; // set global flag
}
//ATtiny low power using interrupt to wake
#include <avr/sleep.h>
#include <avr/interrupt.h>
const int switchPin = 3;
const int statusLED = 2;
void setup() {
pinMode(switchPin, INPUT);
pinMode(statusLED, OUTPUT);
// Flash quick sequence so we know setup has started
for (int k = 0; k < 5; k++) {
if (k % 2 == 0) {
digitalWrite(statusLED, HIGH);
}
else {
digitalWrite(statusLED, LOW);
}
delay(250);
} // for
} // setup
void sleep() {
GIMSK |= _BV(PCIE); // Enable Pin Change Interrupts
PCMSK |= _BV(PCINT3); // Use PB3 as interrupt pin
ADCSRA &= ~_BV(ADEN); // ADC off
set_sleep_mode(SLEEP_MODE_PWR_DOWN); // replaces above statement
sleep_enable(); // Sets the Sleep Enable bit in the MCUCR Register (SE BIT)
sei(); // Enable interrupts
sleep_cpu(); // sleep
cli(); // Disable interrupts
PCMSK &= ~_BV(PCINT3); // Turn off PB3 as interrupt pin
sleep_disable(); // Clear SE bit
ADCSRA |= _BV(ADEN); // ADC on
sei(); // Enable interrupts
} // sleep
ISR(PCINT0_vect) {
// This is called when the interrupt occurs, but I don't need to do anything in it
}
void loop() {
sleep();
digitalWrite(statusLED, HIGH);
delay(1000);
digitalWrite(statusLED, LOW);
}
Comments