Usually they are used for low level tracing and profiling or signal redirection/duplication.
## FuriHalOs
`--extra-define=FURI_HAL_OS_DEBUG` enables tick, tick suppression, idle and time flow.
There are 3 signals that will be exposed to external GPIO pins:
-`AWAKE` - `PA7` - High when system is busy with computations, low when sleeping. Can be used to track transitions to sleep mode.
-`TICK` - `PA6` - Flipped on system tick, only flips when no tick suppression in progress. Can be used to track tick skew and abnormal task scheduling.
-`SECOND` - `PA4` - Flipped each second. Can be used for tracing RT issue: time flow disturbance means system doesn't conforms Hard RT.
## FuriHalPower
`--extra-define=FURI_HAL_POWER_DEBUG` enables power subsystem mode transitions tracing.
There are 2 signals that will be exposed to external GPIO pins:
-`WFI` - `PB2` - Light sleep (wait for interrupt) used. Basically this is lightest and most non-breaking things power save mode. All function and debug should work correctly in this mode.
-`STOP` - `PC3` - STOP mode used. Platform deep sleep mode. Extremely fragile mode where most of the silicon is disabled or in unusable state. Debugging MCU in this mode is nearly impossible.