Attiny13 has very, as in very small memory. So if you want it to crunch stuff which seems to be easy for other MCU, it might not have enough memory for it. It cannot for example consistently carry out millis() like in:
long timeStart = millis();
...
if (timeIsUp=0 && millis()-timeStart=>60000)
...
The most that that code will loop is less than 50 seconds in my experience.
As a workaround I was able to make Attiny13 keep track of time for more than 10 minutes by using only integers and using count. The count being incremented after 10 seconds. So example:
for (int i=0; i>10; i++){
delay(10000);
count++;
Then you can use count to keep track of time that has elapsed.
Using millis() is very heavy for Attiny13.
