sleepcortex-m

Wake-up from Deep Power-Down mode causes a reset in LPC1768


I need to minimize the current consumption in my board which uses a LPC1768. Now I don't have any problem with going into Deep Sleep or Power-Down modes and waking up from those modes. I have configured the RTC to generate an interrupt after some predefined time which does wake up the MCU correctly and works just fine.

My problem occurs when I want to go into Deep Power-Down mode which is precisely what I need (its consumes much less power). But after generating the RTC Interrupt the MCU goes into a reset state and starts the execution from the beginning as if someone pushes the reset button!
Now why is that? I read from the documents (like this example: AN10915: Using the LPC1700 power modes) that these three routines are pretty much the same.

I don't understand. There should be no problem according to the example.
I really need to do this otherwise we loose the battery sooner than it is supposed to.


Solution

  • UM10360.pdf, chapter 4.8.4 says: "In Deep Power-down mode, power is shut off to the entire chip" [...]

    That means all data that is not in the RTC backup registers is lost, and the chip will thus restart with a reset.