backup battery monitoring

Driver to monitor the internal backup battery status. More...

Detailed Description

Driver to monitor the internal backup battery status.

The backup battery must be connected with the VBAT pin and GND. On most development boards you will have to remove a solder bridge that connects VDD with VBAT. The battery is used to retain the backup domain register and RTC register content while power (VDD) is off.

The actual driver is implemented as a CPU feature. A board that supports backup battery monitoring via ADC, must #define VBAT_ADC ADC_LINE(x), where x is the index of the internal VBAT ADC line in adc_config[] in periph_conf.h.

Files
file	vbat.h
	Interface of backup battery (VBAT) monitoring.

Functions
int	vbat_init (void)
	Initialize backup battery monitoring.
int32_t	vbat_sample_mv (void)
	Sample backup battery.
bool	vbat_is_empty (void)
	Sample the backup battery and compare the result with the minimum value required to power the backup domain.

Function Documentation

vbat_init()

int vbat_init

(

void

)

Initialize backup battery monitoring.

Return values

!=	0: Failure
0	Success

vbat_is_empty()

bool vbat_is_empty

(

void

)

Sample the backup battery and compare the result with the minimum value required to power the backup domain.

Return values

true	empty
false	not empty

vbat_sample_mv()

int32_t vbat_sample_mv

(

void

)

Sample backup battery.

Returns

Backup battery load in mV