An old thread was not answered at the time and was in a funny place so I bring back here.
Is anyone able to bring chip out of sleep mode without external trigger.
Is chip able to count 30 minutes while in sleep mode then wake up . Any other way to count externally to 30 min then trigger wake up.
Any new thought here?
I see this comment at http://www.sensor-networks.org/index.php?page=0820520514 but do not understand?
In Arduino we are going to use power save mode to save power and as interrupt source we are going to use the overflow interrupt in timer 2.
Timer 2 is a 8 bit counter (counts until 255) and is able to trigger an overflow interrupt if we also use a 10 bits preescaler we divide the frecuency by 1024 and we get an interrupt source that is triggered 61 times per seconds (16000000 / 1024 / 255 = 61).
This is what I need .How can I program to do this and bring back after 30 minutes
From Data sheet ATMega328 9.5 Power-down Mode When the SM2..0 bits are written to 010, the SLEEP instruction makes the MCU enter Power- down mode. In this mode, the external Oscillator is stopped, while the external interrupts, the 2- wire Serial Interface address watch, and the Watchdog continue operating (if enabled). Only an External Reset, a Watchdog System Reset, a Watchdog Interrupt, a Brown-out Reset, a 2-wire Serial Interface address match, an external level interrupt on INT0 or INT1, or a pin change interrupt can wake up the MCU. This sleep mode basically halts all generated clocks, allowing operation of asynchronous modules only. Note that if a level triggered interrupt is used for wake-up from Power-down mode, the changed level must be held for some time to wake up the MCU. Refer to ”External Interrupts” on page 70 for details. When waking up from Power-down mode, there is a delay from the wake-up condition occurs until the wake-up becomes effective. This allows the clock to restart and become stable after having been stopped. The wake-up period is defined by the same CKSEL Fuses that define the Reset Time-out period, as described in ”Clock Sources” on page 27.
I can turn off Watchdog and ADC and others and bring back on when awake. I look for the code to turn everything off except one timer to count the 30 minutes then bring it back and turn them all on again. I have external occillator crystal operating on the arduino board anyway