stefano gottardi

MCF51QE128 - Issue on waking up from Stop3 mode

Discussion created by stefano gottardi on Oct 13, 2009
Latest reply on Mar 30, 2010 by Leonardo Gabrielli

Hello all,

I'm experiencing a big trouble with MCF51QE128 configuring low power mode in a battery supplied device.


The MCU is supposed to get into Stop3 mode by "_Stop" call; and it's supposed to wake up every 1 second on RTC interrupt. Well, it wakes up for just 32seconds (always 32 seconds!) and then it gets stuck (no wake up for any reason) with costant power consuption (about 20 micro Amps).


MCU configuration:

- RTC clocked by external Osc 32.768 KHz

- MCU clocked by FLL (32.768 Khz x 1024 = 33.554 MHz).

- SPMSC2_LPR = 1;



- On Stop call:

  SPMSC1_LVDSE = 0;  // required to activate Stop3 Mode


  SPMSC2_LPR = 1;



Can anyone help me?

Thanks in advance