sd_nvic_region_enter/exit

[Lucas]

In regard to the following functions

uint32_t sd_nvic_critical_region_enter ( uint8_t * p_is_nested_critical_region ) uint32_t sd_nvic_critical_region_exit ( uint8_t is_nested_critical_region )

It appears that these functions keep track of nested critcal regions for us. How are they to be used. I have just been passing in a local variable (is_nested). Do the functions themselves manage the value of the variable for me. Should they be made global? Or is local fine?

Also will these functions disable all user mode interrupts? Software-timers, hw timers, serial communication, ect... I assume they leave the critical soft device interrupts enabled?

Thank you for the support.

[John]

Hi,

As long as you are willing to limit your entering and exiting critical regions to the same scope, you can use the macros CRITICAL_REGION_ENTER and CRITICAL_REGION_EXIT in app_util.h. The macros deal with the is nested variable for you.

I think it is clear from the implementation of the macros that sd_nvic_critical_region_enter determines if the region is nested and you must keep track of that in the variable. I think locals would definitely be better. Otherwise once the global is set, how do you know when you have fully exited the nested regions?

Regards, John

[Lucas]

From what you describe this sudo code should be valid

f2() {

uint8_t is_nested;

sd_nvic_critical_region_enter ( &is_nested ) ;

sd_nvic_critical_region_exit ( is_nested );

}

f1() {

uint8_t is_nested;

sd_nvic_critical_region_enter ( &is_nested ) ;

f2();

sd_nvic_critical_region_exit ( is_nested );

}

f2 would not cause the program to leave the critical region correct.