In one of our application, we are using LPC2364 controller. As the application requires good power management we are putting LPC2364 into SLEEP MODE periodically (1 min,2 min etc). Following is the issue we are facing during this power management routine:
1) The power down mode used here is SLEEP MODE 2) To wake-up controller from SLEEP MODE, we are using RTC as the interrupt source. The RTC interrupt occurs every 1 Minute. 3) After this interrupt, as per the technical literature we are checking the status of OSCSTAT register (To confirm if the oscillator is stable) and after this we are reconfiguring the PLL (PLL function is getting called Inside the RTC Interrupt) 4) After PLL is reconfigured, the controller power mode is changed to normal working mode to resume the operation.
Problem :
The main issue we are facing is the controller does not resume its operation after coming out from sleep mode. Sometimes this happens properly and the controller performs its operation. We think that the controller able to wake up properly. Also the controller restarts from the SLEEP MODE instead of coming out to resume the operation.(In this case the reset source is none of the standard reset sources that are monitored)
Kindly advice on this issue. What could be the possible cause?