Cyrille Goiz

MC9S08QE128 STOP3 RTC waking up using alternatively ICS 32kHz and LPO 1khz

Discussion created by Cyrille Goiz on Sep 19, 2008
Latest reply on Dec 21, 2009 by Cyrille Goiz

I've succeeded in implementing STOP3 mode with LPO 1kHz OR with ICS 32 kHz (separately)
=> MCU enter stop3 mode then is waked up by RTC (or KBI).

But when I tried the following sequence :

Enter stop3 mode with ICS 32kHz => waking up after ~100ms (run mode) => 1s later, enter stop3 with LPO 1khz (RTC timer = 1s) => MCU cannot be waked up by RTI (but it can be waked up by KBI) !!!

Note : The sequence {STOP3 LPO 1kHz => waking up => STOP3 ICS 32 kHz => waking up} works....

according to MC9S08QE128_0M11J.pdf errata sheet
=> I've a delay of 1ms before each stop instruction (I've tried with 10ms, 100ms)
=> STOP instruction is executed out of RAM memory instead of from flash memory .
=> SCGC2_RTC is always clocked (even if LPO 1khz is used)

does anyone see where could be the problem ?

Thanks !