9S12DJ64 timer module does not generate interrupt on stop?

68HC912B32Guy — Mon, 23 Aug 2010 04:55:34 GMT

Hello. I seem to be unable to get the timer module to wake up the processor after a STOP instruction. However, after a WAI instruction, the timer will wake up the processor and service the interrupt. Is the timer module not able to generate an interrupt in STOP mode?

The code that initializes the timer channel looks like this and allows me to capture the waveform I have on the IC0 pin just fine:
clr          TIE                    ;disable interrupts
movb   #%00000101,TSCR2   ;output compare resolution is 8 us, prescaler=32, 4 MHz clock
movb    #$02,TCTL4            ;init IC0 for falling edge detection
clr          TIOS                      ;select channel 0 to act as input capture (IC)
movb    #$80,TSCR1               ;enable timer, runs during BDM and in wait, clears flags normally

The code that I use right before I stop the processor looks like this:
movb    $03,TCTL4               ;init IC0 for rising and falling edges detection
bset   TIE,#$01                 ;enable TM0 interrupt
ldaa   TFLG1
movb    #$FF,TFLG1              ;clear any interrupts on the timer channels
andcc   #$7F                       ;enable CPU standby mode via STOP
cli                                               ;enable global interrupts
stop

Am I making a mistake leading up to the STOP instruction? No amount of activity on timer channel 0 wakes up the processor.

Thank you!

Re: 9S12DJ64 timer module does not generate interrupt on stop?

kef — Mon, 23 Aug 2010 13:07:11 GMT

Timer requires clock to run. And since STOP mode shuts off all clocks, timer can't operate.

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9S12DJ64 timer module does not generate interrupt on stop?

Re: 9S12DJ64 timer module does not generate interrupt on stop?