Hello.Please can i have help, hints or ideas?I'm trying to wake up from vlls3 mode using a switch on a pin, but something goes wrong.
I reduced code at example level to better focus on the problem:after reset 1)initialization2)an easy recognizable 4 seconds square wave is outputted on a pin,3) an infinite loop is entered,where another sequence of different frequency is repeatedly outputted,and the status of a button is polled;
if pressed ,the vlls3 mode is called,just after the button itself is configured as wakeup trigger source,then the uC goes to sleep in vlls3 mode.
Resumed code looks like this:
void main(void){
wdog_disable();
PE_low_level_init();
TogglePin2KHz_4Sec();//to see it on oscilloscope when it passes through this point,once-only
for(;;)//infinite loop {
TogglePin500Hz_1Sec();//to see it on oscilloscope when it passes through this point,repeatedly
if(BUTTON PRESSED) {
..... //prepare Button as wake up trigger event
asm("WFI")
}//end of if
}//end of for(;;)
}//end of main
I measure the power consumption by 1 ohm resistor and a digital multimeter with less significative digit representing 0.1uV->100nA(probably not actually),i tried to follow tips from AN4503 11.1.2 Tips for making low-power measurements on the bench.
I can see current absorption =20 mA in RUN mode,and few uA when i call vlls3,,so i can think to be entered in vlls3.Ok until there.
Pushing the button the absorption rises up to 20 mA,typical of RUN mode,but i can't see any square wave on the scope.Where is my program running?
Debugging with Cyclone Max adds hundreds of uA,but that is non the main problem, i can see the debug stopping during vlls3.When,i turn back in RUN mode the debugger appears able to follow the code,but no signal on output pin when code should toggle it.If i check registers inherent to that PORT_PIN they look unchanged,if compared to the previous RUN mode.Is the debug realistic?
Reading the AN4503 at page 31:
• VLLSx exits to Run mode through the reset flow.
• For Kinetis devices, after exit from VLLSx, execution starts with the instruction pointed to by the RESET vector address.
I should expect that the the code starts from RESET,initializing stack pointer,global variables etc.It is my expectation wrong?
In code examples i found that at least GPIO iniatilization is done in wake up ISR,so i done(see attached file).
Thanks for your attention,
Diego.
Original Attachment has been moved to: Test_VLLS3.c.zip
