A state machine to monitor a LiPo battery and charger. More...

#include <nrfcxx/misc/lipomon.hpp>

Inheritance diagram for nrfcxx::misc::lipo_monitor:

Public Types
enum	PowerSource_e : uint8_t { PS_Unknown = 0, PS_OnBattery = 1, PS_Charging = 2, PS_Charged = 3 }
	State of power source as inferred from VCHG_DETECT and BAT_CHG_STAT signals. More...

Public Member Functions
	lipo_monitor (notifier_type notify, const gpio::gpio_pin &vchg_detect, const gpio::gpio_pin &chgn_state, sensor::adc::voltage_divider &battmeas)
	Construct an instance. More...

bool	vchg_detected_live ()
	Read the live USB detection signal.

bool	charging_live ()
	Read the live charging signal.

int	calibrate ()
	Initiate a calibration of the ADC used to measure voltage. More...

int	batt_mV () const
	The most recently collected LiPo output voltage. More...

int	power_source () const
	Get the latest processed power source. More...

Public Member Functions inherited from nrfcxx::lpm::lpsm_capable
virtual int	lpsm_start ()
	Validate and prepare to initiate an LPM collection. More...

virtual int	lpsm_sample ()
	Ask the LPM infrastructure to initiate a new sample. More...

lpm::state_machine::process_flags_type	lpsm_process ()
	Make progress on an LPM collection. More...

int	lpsm_stop ()

int	lpsm_reset ()

int	lpsm_process_rc () const
	Get the internal result code from the last invocation of lpsm_process_(). More...

const lpm::state_machine &	machine () const
	Gain read-only access to the LPM machine state.

Static Public Attributes
static constexpr auto	PF_STARTED = lpm::state_machine::PF_STARTED

static constexpr auto	PF_LIPO = lpm::state_machine::PF_APP_BASE
	Sensor-specific indication from lpm::lpsm_capable::lpsm_process() that a powered USB cable has been removed and the system is running from battery power.

static constexpr auto	PF_MAINS = lpm::state_machine::PF_APP_BASE << 1
	Sensor-specific indication from lpm::lpsm_capable::lpsm_process() that a powered USB cable has been inserted and the system is running from mains power. More...

static constexpr auto	PF_CHARGING = lpm::state_machine::PF_APP_BASE << 2
	Sensor-specific indication from lpm::lpsm_capable::lpsm_process() that the LiPo battery is being charged from a mains power source.

static constexpr auto	PF_CHARGED = lpm::state_machine::PF_APP_BASE << 3
	Sensor-specific indication from lpm::lpsm_capable::lpsm_process() that the LiPo battery has completed charging.

static constexpr auto	PF_CALIBRATED = lpm::state_machine::PF_APP_BASE << 5
	Sensor-specific indication from lpm::lpsm_capable::lpsm_process() that the battery voltage sensor has been calibrated.

Additional Inherited Members
Protected Types inherited from nrfcxx::lpm::lpsm_capable
using	state_type = state_machine::state_type

using	process_flags_type = state_machine::process_flags_type

Protected Member Functions inherited from nrfcxx::lpm::lpsm_capable
	lpsm_capable (notifier_type notify)
	Create a state machine that records state and supports delayed transitions. More...

virtual int	lpsm_process_ (int &delay, process_flags_type &pf)
	Override to implement machine-specific operations of lpsm_process(). More...

virtual void	lpsm_reset_ ()
	Override to reset state that is held outside the machine.

Protected Attributes inherited from nrfcxx::lpm::lpsm_capable
state_machine	machine_

Detailed Description

A state machine to monitor a LiPo battery and charger.

This class does several things:

Monitors a VCHG_DETECT signal that indicates whether a charging voltage is available;
Monitors a CHGn_STATE signal that is low when charging is active;
Maintains the current power source status;
Supports on-request sampling of the LiPo output voltage.

lpm::lpsm_capable::lpsm_process() for this sensor returns the following flags:

lpm::state_machine::PF_STARTED when BAT_MON_EN has been asserted. On receipt calibrate() should be invoked;
lpm::state_machine::PF_OBSERVATION when a new battery voltage measurement is available from batt_mV();
PF_LIPO when the system is discovered to be running on battery;
PF_MAINS when the system is discovered to be running on external power;
PF_CHARGING when the LiPo battery begins charging from external power;
PF_CHARGED when the LiPo battery completes charging from external power;
PF_CALIBRATED when ADC calibration completes, allowing lpm::lpsm_capable::lpsm_sample() to be successfully invoked.

calibrate() should be invoked by the application on startup and whenever the ambient temperature changes by more than 10 Cel from the last calibration.

Member Enumeration Documentation

◆ PowerSource_e

enum nrfcxx::misc::lipo_monitor::PowerSource_e : uint8_t

State of power source as inferred from VCHG_DETECT and BAT_CHG_STAT signals.

Enumerator
PS_Unknown	No information available.
PS_OnBattery	V_BUS is zero. Values greater than this have V_BUS non-zero.
PS_Charging	V_BUS is non-zero and TCK106 charging active.
PS_Charged	V_BUS is non-zero and TCK106 charging not active.

Constructor & Destructor Documentation

◆ lipo_monitor()

nrfcxx::misc::lipo_monitor::lipo_monitor	(	notifier_type	notify,
		const gpio::gpio_pin &	vchg_detect,
		const gpio::gpio_pin &	chgn_state,
		sensor::adc::voltage_divider &	battmeas
	)

Construct an instance.

Parameters

notify	the setter used to indicate to the application that lpsm_process() should be invoked.
vchg_detect	a GPIO reference that is high when a charging voltage is available, and low when it is not.
chgn_state	a GPIO reference that is low when the battery is being charged, and high when it is not being charged. The signal is considered valid only when a charging voltage is available.
battmeas	the ADC client used to measure the voltage of the LiPo battery. A reference to this instance will be retained.

Member Function Documentation

◆ batt_mV()

int nrfcxx::misc::lipo_monitor::batt_mV ( ) const

inline

The most recently collected LiPo output voltage.

Note: A negative value indicates that the collection occurred when the system was externally powered, a condition in which the measured power may inaccurately represent the true state of the LiPo.

◆ calibrate()

int nrfcxx::misc::lipo_monitor::calibrate ( )

Initiate a calibration of the ADC used to measure voltage.

Returns: zero on success, negative if the state machine is busy.

◆ power_source()

int nrfcxx::misc::lipo_monitor::power_source ( ) const

Get the latest processed power source.

Note: The value returned here is not live, but the state as observed in the last invocation of lpsm_process().

Returns: An enumeration value from PowerSource_e or a negative error code.

Field Documentation

◆ PF_MAINS

constexpr auto nrfcxx::misc::lipo_monitor::PF_MAINS = lpm::state_machine::PF_APP_BASE << 1

staticconstexpr

Sensor-specific indication from lpm::lpsm_capable::lpsm_process() that a powered USB cable has been inserted and the system is running from mains power.

If this flag is returned either PF_CHARGING or PF_CHARGED will appear with it.

The documentation for this class was generated from the following file:

nrfcxx/misc/lipomon.hpp

Public Types

Public Member Functions

Static Public Attributes

Additional Inherited Members