How to exit a function

[ignis]

The stdlib.h file contains a exit() function, but my compiler complains when I try to use that.

How can I completely shut-off a MCU (from code) so that it consumes no more power?

[filip]

Hi,

From code, you can put it in the Sleep mode, in which it will consume minimal power.

Regards,
Filip.

[ignis]

From code, you can put it in the Sleep mode, in which it will consume minimal power.

Filip.

Thanks, but I want to do better than sleep. I want to shut-down the MCU and consume no power. Is that possible?

[filip]

Hi,

Unfortunately, this cannot be achieved from the code as far as I know.

Regards,
Filip.

[Sparky1039]

Thanks, but I want to do better than sleep. I want to shut-down the MCU and consume no power. Is that possible?

If the MCU is completely shut down how do you expect to wake it back up?
What you should consider is using a PIC that offers the XLP capability. If done right the sleep current on some of these parts can be as low as 20-60nA, which in many cases is far lower than the self consumption rate of many battery technologies.
http://www.microchip.com/en_us/technolo ... ducts.html

[ignis]

Thanks, but I want to do better than sleep. I want to shut-down the MCU and consume no power. Is that possible?

If the MCU is completely shut down how do you expect to wake it back up?
What you should consider is using a PIC that offers the XLP capability. If done right the sleep current on some of these parts can be as low as 20-60nA, which in many cases is far lower than the self consumption rate of many battery technologies.
http://www.microchip.com/en_us/technolo ... ducts.html

For my application, I can re-power the unit to get it going again.

I think your solution may work here. I'll do some research and give it a try. Thanks.

[Sparky1039]

If you are going to power cycle the device you might consider this circuit.

PIC switch.png (46.03 KiB) Viewed 2610 times

The push button initally routes power around the p-ch fets to get the PIC powered up. Once the PIC is running the first task is to clear the port tied to the p-ch fet gates (low). This will sustain VDD once the push button is opened. When the time comes to kill power the PIC sets the mosfet gates high. This shuts down everything and a button push is the only way to get it started again.
Using 2 mosfets reduces leakage in the off state.