I'm a newb when it comes to sleep modes so I'd appreciate some guidance from those who aren't. I'm using an ATTiny85, running of the internal 8MHz oscillator and use the following code to put it to sleep (power-down mode):
SREG = 0x80; // Enable interrupts. Wait for button press. MCUCR |= 0x30; // Set sleep enable bit, power-down mode asm("sleep"); // Go to sleep while(!(push)) ;
When awake (on a pin-change interrupt), the part draws about 4 mA. When asleep, 2.9 mA. I expected a much bigger savings (as in drawing uAs. Am I doing something wrong, or confused, or both? Thanks.