RpmMonitor Class Reference

Measures fan speed from tachometer pulses. More...

#include <rpm_monitor.h>

Public Member Functions
	RpmMonitor (const RpmMonitorConfig &config=kDefaultRpmMonitorConfig)
	Creates an RPM monitor with the supplied tachometer configuration.
bool	begin ()
	Initializes the tachometer pin and attaches the interrupt handler.
void	update (uint32_t nowMs)
	Updates the measured RPM after the configured sample window elapses.
uint16_t	rpm () const
	Returns the most recently calculated fan speed.
uint32_t	pulseCount () const
	Returns the number of pulses accumulated in the current sample.
uint32_t	sampleAgeMs (uint32_t nowMs) const
	Calculates the age of the current RPM sample.

Detailed Description

Measures fan speed from tachometer pulses.

The monitor attaches an interrupt to the tachometer pin, counts falling edges, and converts each completed sample window to revolutions per minute. Only one active instance is supported because the interrupt trampoline is shared.

RPM is rounded to the nearest integer over the elapsed sample window. Reading and clearing the volatile pulse counter is protected by temporarily disabling interrupts, keeping the ISR simple and the sampling result consistent.

Constructor & Destructor Documentation

RpmMonitor()

RpmMonitor::RpmMonitor ( const RpmMonitorConfig &  config = kDefaultRpmMonitorConfig )

explicit

Creates an RPM monitor with the supplied tachometer configuration.

Parameters

config

Tachometer pin, pulses-per-revolution, and sample window.

Member Function Documentation

begin()

bool RpmMonitor::begin

(

)

Initializes the tachometer pin and attaches the interrupt handler.

Returns

True when initialization completed.

pulseCount()

uint32_t RpmMonitor::pulseCount

(

)

const

Returns the number of pulses accumulated in the current sample.

Returns

Unsampled tachometer pulse count since the last RPM calculation.

rpm()

uint16_t RpmMonitor::rpm

(

)

const

Returns the most recently calculated fan speed.

Returns

Last measured RPM, rounded to the nearest integer.

sampleAgeMs()

uint32_t RpmMonitor::sampleAgeMs

(

uint32_t

nowMs

)

const

Calculates the age of the current RPM sample.

Parameters

nowMs

Current monotonic timestamp in milliseconds.

Returns

Elapsed milliseconds since the last completed sample.

update()

void RpmMonitor::update

(

uint32_t

nowMs

)

Updates the measured RPM after the configured sample window elapses.

Call this regularly from the main loop with the current millis() value.

Parameters

nowMs

Current monotonic timestamp in milliseconds.

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

• firmware/controller/rpm_monitor.h
• firmware/controller/rpm_monitor.cpp