in system off mode , while(1) keep running ?

[ToTo]

Hi,

I used the app of nordic , that puts the system off in order to measure the current at that mode. the example i used is at this link. ( system-off-wakeup-on-gpio )

I debuged the program, and i noticied that even after going to off mode, the while (1) keep being executed. Is it logic ?

1-The button_0 used to enter mode off(configured with this function :nrf_gpio_cfg_input()), is still has an effect in off mode (that mean when i clik on it on off mode current consumption increases ) , why? in off mode such button consumption impact is stopped no ?

2-waking up from off mode is only with a hard reset or button click that is configured using this function : nrf_gpio_cfg_sense_input();

3-What are the stuff keep running or on after entering in system off ? im really confused ..

[Susheel Nuguru]

Hi ToTo,

In debug mode (while your debugger is controlling the chip) the System-OFF mode is emulated, which means that the chip really does not go to system off to keep the debugger link alive.

Please read about the emulated system off mode here

When in System OFF , all power regulators except for power reset and wakeup source are powered off. When the wakeup source is detected, it will wake the chip, reset the chip and enable all the power regulators.

Now this is what happens in emulated system off (debugger connected). The power regulators are not turned off, that is the reason you need while(1); because the CPU will still be running. But the wakeup source will just reset the chip (because it do not need to power on regulators as they were not turned off in emulated mode). This behaves exactly same like actual system off in debugger except that the the CPU is still running and power consumption is higher. This is very useful feature for debugging system off feature.

I hope that it made things clear.

[ToTo]

Very clear guy, thanks ;)