MC9S08QG8 Stop Mode 2, Exit with RTI -> How?

chumpykid — Wed, 14 Jun 2006 00:55:50 GMT

Being new to this processor, I'm having trouble finding the correct way to enter/exit Stop Mode 2 from RTI. Enter stop mode in main, then somehow exit in the RTI. Below is minimal code to use to show an example.... I've enabled stop2 in SPMSC2= 0x03 and STOPE in SOPT1. Any help would be appreciated.

void main(void)
{

// Initialization
MCU_init();

// Enable Interrupts
EnableInterrupts;

   // Background Loop
   while (1)
   {
           // Feed the dog
           __RESET_WATCHDOG();

           // check inputs
           CheckInputs();

           // Put into Stop Mode
           asm stop;
   }
}

// RTI interrupt for Real Time Clock
void interrupt 23 RTI_Isr (void)
{

// Acknowledges RTI Flag
SRTISC_RTIACK = 1;

// Exit Stop Mode 2 here?

// Time Keeping here

}

Re: MC9S08QG8 Stop Mode 2, Exit with RTI -> How?

chumpykid — Sat, 01 Jul 2006 03:57:23 GMT

After some painful tech support... I can almost answer my own question..

Apparently if you have an "asm stop" in a while loop, it doesn't even bother to do the RTI. If in stop mode 1 or stop mode 2, it does a POR, so you do not need to keep this in a loop, although the syntax is correct.

Stop Mode 3, I have yet to get it working correctly. Stop Mode 3 does not do the POR, so you must keep it in some sort of loop. I do see an overall drop in current, but not the results I would expect.

topic Re: MC9S08QG8 Stop Mode 2, Exit with RTI -> How? in 8-bit Microcontrollers

MC9S08QG8 Stop Mode 2, Exit with RTI -> How?

Re: MC9S08QG8 Stop Mode 2, Exit with RTI -> How?