You can use the programs in the post here in arduino with an attiny85 but the millis() returns 0. It seems that this is because the arduino sw wants a void setup() and void loop() definitions. The program below works.

/*

From http://brownsofa.org/blog/archives/261
Led current on on, ~0mA off.
Not 1 second. Needs more accuracy for cameratimer.

*/

#include
#include
#include
SoftwareSerial mySerial(1,3);

ISR(WDT_vect) {
// Toggle Port B pin 4 output state
digitalWrite(4,!(digitalRead(4)));
}

void setup(){
// set serial out on pb3
mySerial.begin(9600);

// Set up Port B pin 4 mode to output
pinMode(4, OUTPUT);
pinMode(3, OUTPUT);

// temporarily prescale timer to 1s so we can measure current
WDTCR |= (1<<WDP1) | (1<<WDP2); // (1<<WDP2) | (1<<WDP0);

// Enable watchdog timer interrupts
WDTCR |= (1<<WDIE);

sei(); // Enable global interrupts

// Use the Power Down sleep mode
set_sleep_mode(SLEEP_MODE_PWR_DOWN);

mySerial.print("Starting…");
}

void loop(){

mySerial.println(millis());
sleep_mode(); // go to sleep and wait for interrupt…
}

I searched like a maniac to resolve this issue on my Leopard installation. So far I have had reason to use these instructions twice and they put an end to hours of trial and error. Just thought I’d take the time to let you know that this post really helped me and I really appreciate that you took the time to write it.

Thanks!