CM/XP Auto-on circuit
« on: May 11th, 2008, 9:23am »
Here is a lo-power (4.5uA measured by me ) timing circuit which will turn-on your OrgII after a 5mins delay. Or modify easily for other intervals.
It uses a CMOS 4060 counter chip worth less than $1, and not much else!
Power is from SS3; when Org is off this pin can still supply the required current via its 47K internal pullup
The 4060 has inbuilt inverters which can be used as an oscillator. This then feeds the chain of dividers, and any output can be used to trigger the 'AC' input of the Org.
Lo-going pulse to 'AC' input is via a capacitor, as otherwise the counter output when in its low state will keep turning the Org on.
As setup in the circuit attached, you can use a LED to aid in fine-tuning the oscillator if needed.
The counter is reset and held at zero when its reset line is 'hi', so activating slot3 Vcc does that directly, and when the slot power is removed at the 'OFF' command,
the counter starts again from zero.
Obviously, your software will need to do that, but assuming the 'AC' wake-up is being used for say data-logging, then the slot will be made active anyway and the reset will be taken care of automatically.