mass_flow_meter.cpp File Reference

Mass Flow meter management. More...

#include "../includes/mass_flow_meter.h"
#include <Arduino.h>
#include <HardwareSerial.h>
#include <IWatchdog.h>
#include <OneButton.h>
#include <Wire.h>
#include <math.h>
#include "../includes/buzzer_control.h"
#include "../includes/config.h"
#include "../includes/parameters.h"
#include "../includes/screen.h"

Go to the source code of this file.

Macros
#define	MASS_FLOW_TIMER_FREQ   10000
#define	MASS_FLOW_PERIOD   100
#define	MFM_MEAN_SAMPLES   40
#define	MFM_WAIT_RESET_PERIODS   13
#define	MFM_WAIT_WARMUP_PERIODS   8
#define	MFM_WAIT_SOFTRESET_PERIODS   3
#define	MFM_WAIT_READSERIALR1_PERIODS   1

Functions
void	MFM_Timer_Callback (HardwareTimer *)
bool	MFM_init (void)
	Initialize Mass Flow Meter. More...
int32_t	MFM_read_airflow (void)
	Read instant air flow. More...
int32_t	MFM_expi_read_airflow (void)
	Read instant air flow. More...
void	MFM_reset (void)
	Reset the volume counter. More...
void	MFM_expi_reset (void)
uint32_t	MFM_read_serial_number (void)
	Get the serial number of the inspiratory flow meter. More...
uint32_t	MFM_expi_read_serial_number (void)
	return the serial number of the expiratory flow meter More...
int8_t	MFM_calibrateZero (void)
	If the massflow meter needs to be calibrated, this function will be usefull. More...
int32_t	MFM_getOffset (void)
	Get massflow meter offset. More...
int32_t	MFM_read_milliliters (bool reset_after_read)
	Get the number of milliliters since last reset. More...
int32_t	MFM_expi_read_milliliters (bool reset_after_read)
	Get the number of milliliters since last reset for expiratory sensor. More...

Variables
volatile uint16_t	MFM_force_release_I2C = MFM_FORCE_RELEASE_I2C_FALSE
uint32_t	mfmHoneywellHafSerialNumber = 0
uint32_t	mfmSfm3300SerialNumberExpi = 0
uint32_t	mfmSfm3019SerialNumber = 0
HardwareTimer *	massFlowTimer = NULL
volatile bool	mfmFaultCondition = false
volatile int32_t	mfmInspiratoryCalibrationOffset = 0
volatile int32_t	mfmInspiratoryAirVolumeSumMilliliters = 0
volatile int32_t	mfmInspiratorySensorDetected = 0
volatile int32_t	mfmInspiratoryInstantAirFlow = 0
volatile int32_t	mfmExpiratoryCalibrationOffset = 0
volatile int32_t	mfmExpiratoryAirVolumeSumMilliliters = 0
volatile int32_t	mfmExpiratorySensorDetected = 0
volatile int32_t	mfmExpiratoryInstantAirFlow = 0
volatile bool	mfmInspiratoryInstantAirFlowRecord = false
volatile int32_t	mfmInspiratoryInstantAirFlowLastValues [MFM_MEAN_SAMPLES]
volatile int16_t	mfmInspiratoryInstantAirFlowLastValuesIndex = 0
int32_t	mfmInspiratoryLastValue = 0
volatile int32_t	mfmInspiratoryLastValueFixedFloat = 0
volatile int32_t	mfmExpiratoryLastValueFixedFloat = 0
int32_t	mfmResetStateMachine = MFM_WAIT_RESET_PERIODS
uint16_t	mfmExpiSFM3300FailCounter = 0
union {
uint16_t   i
int16_t   si
unsigned char   c [2]
}	mfmLastData

Detailed Description

Mass Flow meter management.

Author

Makers For Life

Copyright

Copyright (c) 2020 Makers For Life

SFM3300-D sensirion mass flow meter is connected on I2C bus. To perform the integral of the mass flow, I2C polling must be done in a high priority timer.

Definition in file mass_flow_meter.cpp.

Macro Definition Documentation

MASS_FLOW_PERIOD

#define MASS_FLOW_PERIOD   100

Definition at line 42 of file mass_flow_meter.cpp.

MASS_FLOW_TIMER_FREQ

#define MASS_FLOW_TIMER_FREQ   10000

Definition at line 39 of file mass_flow_meter.cpp.

MFM_MEAN_SAMPLES

#define MFM_MEAN_SAMPLES   40

Definition at line 66 of file mass_flow_meter.cpp.

MFM_WAIT_READSERIALR1_PERIODS

#define MFM_WAIT_READSERIALR1_PERIODS   1

Definition at line 83 of file mass_flow_meter.cpp.

MFM_WAIT_RESET_PERIODS

#define MFM_WAIT_RESET_PERIODS   13

Definition at line 80 of file mass_flow_meter.cpp.

MFM_WAIT_SOFTRESET_PERIODS

#define MFM_WAIT_SOFTRESET_PERIODS   3

Definition at line 82 of file mass_flow_meter.cpp.

MFM_WAIT_WARMUP_PERIODS

#define MFM_WAIT_WARMUP_PERIODS   8

Definition at line 81 of file mass_flow_meter.cpp.

Function Documentation

MFM_calibrateZero()

int8_t MFM_calibrateZero

(

void

)

If the massflow meter needs to be calibrated, this function will be usefull.

Calibrate the zero of the sensor.

Definition at line 604 of file mass_flow_meter.cpp.

                               {
    int8_t ret = MFM_CALIBRATION_OK;
    // activate table fill with last valid value
    mfmInspiratoryInstantAirFlowLastValuesIndex = 0;
    mfmInspiratoryInstantAirFlowRecord = true;
    // wait for the table to fill in
    delay(2 + (MFM_MEAN_SAMPLES * (MASS_FLOW_PERIOD / 10)));
    // Check that table is full (record must be false)
    // If it is not, there is a sensor problem
    // In case of problem, do not update mfmInspiratoryCalibrationOffset
    if (!mfmInspiratoryInstantAirFlowRecord) {
        int32_t zeroFlow = 0;
        for (int16_t i = 0; i < MFM_MEAN_SAMPLES; i++) {
            zeroFlow += mfmInspiratoryInstantAirFlowLastValues[i];
        }
        zeroFlow /= MFM_MEAN_SAMPLES;
        // check that value is credible: [-10 10] SLPM
        if ((zeroFlow < 10000) && (zeroFlow > -10000)) {
            mfmInspiratoryCalibrationOffset = zeroFlow;
        } else {
            ret = MFM_CALIBRATION_OUT_OF_RANGE;
        }
    } else {
        ret = MFM_CALIBRATION_IMPOSSIBLE;
    }
    return ret;
}

MFM_expi_read_airflow()

int32_t MFM_expi_read_airflow

(

void

)

Read instant air flow.

Definition at line 566 of file mass_flow_meter.cpp.

                                    {
    int32_t r;
    if (mfmFaultCondition) {
        r = MASS_FLOW_ERROR_VALUE;
    } else {
        r = mfmExpiratoryInstantAirFlow - mfmExpiratoryCalibrationOffset;
    }
    return r;
}

MFM_expi_read_milliliters()

int32_t MFM_expi_read_milliliters

(

bool

reset_after_read

)

Get the number of milliliters since last reset for expiratory sensor.

Parameters

reset_after_read

If true, performs the volume reset in the same atomic operation

Returns

Volume of air that went through sensor since last reset in mL

Definition at line 654 of file mass_flow_meter.cpp.

                                                         {
    int32_t result = MASS_FLOW_ERROR_VALUE;
 
#if MASS_FLOW_METER_SENSOR_EXPI == MFM_SFM_3300D
    result = mfmFaultCondition
                 ? MASS_FLOW_ERROR_VALUE
                 : ((mfmExpiratoryAirVolumeSumMilliliters * MASS_FLOW_PERIOD) / (60 * 10000));
#endif
    if (reset_after_read) {
        MFM_expi_reset();
    }
 
    return result;
}

MFM_expi_read_serial_number()

uint32_t MFM_expi_read_serial_number

(

void

)

return the serial number of the expiratory flow meter

Get the serial number of the expiratory flow meter.

Note

returns 0 before init, or if init failed.

Definition at line 597 of file mass_flow_meter.cpp.

{ return mfmSfm3300SerialNumberExpi; }

MFM_expi_reset()

void MFM_expi_reset

(

void

)

Definition at line 578 of file mass_flow_meter.cpp.

{ mfmExpiratoryAirVolumeSumMilliliters = 0; }

MFM_getOffset()

int32_t MFM_getOffset

(

void

)

Get massflow meter offset.

Definition at line 635 of file mass_flow_meter.cpp.

{ return mfmInspiratoryCalibrationOffset; }

MFM_init()

bool MFM_init

(

void

)

Initialize Mass Flow Meter.

Returns

True if there is a Mass Flow Meter connected

Warning

If no Mass Flow Meter is detected, you will always read volume = 0 mL

Definition at line 321 of file mass_flow_meter.cpp.

                    {
    mfmInspiratoryAirVolumeSumMilliliters = 0;
    // cppcheck-suppress unreadVariable
    uint32_t errorCount = 0;
    // Set power on (hardware v3)
    pinMode(MFM_POWER_CONTROL, OUTPUT);
    digitalWrite(MFM_POWER_CONTROL, MFM_POWER_ON);
    delay(100);  // sfm3300 worst case boot time.
 
    // Set the timer
    massFlowTimer = new HardwareTimer(MASS_FLOW_TIMER);
 
    // Prescaler; stm32f411 clock is 100 mHz
    massFlowTimer->setPrescaleFactor((massFlowTimer->getTimerClkFreq() / MASS_FLOW_TIMER_FREQ) - 1);
 
    // Set the period
    massFlowTimer->setOverflow(MASS_FLOW_PERIOD);
    massFlowTimer->setMode(MASS_FLOW_CHANNEL, TIMER_OUTPUT_COMPARE, NC);
    massFlowTimer->attachInterrupt(MFM_Timer_Callback);
 
    // Interrupt priority is documented here:
    // https://stm32f4-discovery.net/2014/05/stm32f4-stm32f429-nvic-or-nested-vector-interrupt-controller/
    // WARNING : since 1.9.0 lib, I2C is on level 2. must be under...
    massFlowTimer->setInterruptPriority(3, 0);
 
    // default Wire instance is on PB8 BP9, anyway
    Wire.setSDA(PIN_I2C_SDA);
    Wire.setSCL(PIN_I2C_SCL);
    // Wire.setClock(400000); // honeywell do support, but no information about sfm3300d
 
#if MASS_FLOW_METER_SENSOR == MFM_SFM3019
    Wire.begin();
    Wire.beginTransmission(0x00);
    Wire.write(0x06);
    Wire.endTransmission();
    Wire.end();
    delay(4);
 
    //     // start air continuous measurement
    //     Wire.begin();
    //     Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
    //     Wire.write(0x36);
    //     Wire.write(0x08);
    //     errorCount += Wire.endTransmission();
    //     Wire.end();
 
    //     delay(2);
    //     //Stop continuous measurement 0x3FF9
    //     Wire.begin();
    //     Wire.beginTransmission(0x2E);
    //     Wire.write(0x3F);
    //     Wire.write(0xF9);
    //     Wire.endTransmission();
    //     Wire.end();
 
    //     delay(2);
    //      //Read Scale Factor, Offset, and Flow Unit 0x3661
    //     Wire.begin();
    //     Wire.beginTransmission(0x2E);
    //     Wire.write(0x36);
    //     Wire.write(0x61);
    //     Wire.endTransmission();
    //     Wire.end();
    // delay(2);
    //     Wire.begin();
    //     int ccc = Wire.requestFrom(0x2E, 8);
    //     Serial.print(ccc);
    //     Serial.print(" ");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
    //     Serial.print(Wire.read()); Serial.print(",");
 
    //     Wire.end();
 
    delay(5);
    // Read serial number
    Wire.begin();
    Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
    Wire.write(0xE1);
    Wire.write(0x02);
    errorCount = Wire.endTransmission();
 
    delay(1);
    errorCount += ((18u == Wire.requestFrom(MFM_SFM3019_I2C_ADDRESS, 18)) ? 0u : 1u);
    if (errorCount == 0u) {
        // the serial number is 64 bits wide, but it will never be used until year 2042.
        // The serial number can be converted from binary into decimal,
        // whereby in decimal it has the following format::
        // yywwxxxxxx, where: yy: last to digits of calibration year, ww:
        // calibration week, xxxxxx: unique 6-digit sequential number
        // within the calibration week.
        uint32_t sn_inspi = 0;
        Wire.read();
        Wire.read();  // product number part 1
        Wire.read();  // crc
        Wire.read();
        Wire.read();  // product number part 2
        Wire.read();  // crc
 
        Wire.read();
        Wire.read();  // ignore this part of serial
        Wire.read();  // ignore inlined crc
        Wire.read();
        Wire.read();  // ignore this part of serial
        Wire.read();  // ignore inlined crc
        sn_inspi |= Wire.read();
        sn_inspi <<= 8;
        sn_inspi |= Wire.read();
        sn_inspi <<= 8;
        Wire.read();  // ignore inlined crc
        sn_inspi |= Wire.read();
        sn_inspi <<= 8;
        sn_inspi |= Wire.read();
        Wire.read();  // ignore inlined crc
        mfmSfm3019SerialNumber = sn_inspi;
    }
    delay(1);
 
    // start air continuous measurement
    Wire.begin();
    Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
    Wire.write(0x36);
    Wire.write(0x08);
    errorCount += Wire.endTransmission();
    Wire.end();
 
    delay(40);  // the first measurement result will be available after 12ms
    // small accuracy deviations (few % of reading) can occur during the first 30ms
 
    // delay(10000);
    if (errorCount != 0u) {
        mfmFaultCondition = true;
        mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
    }
#endif
 
#if MASS_FLOW_METER_SENSOR_EXPI == MFM_SFM_3300D
    Wire.begin();  // Join I2C bus (address is optional for master)
    Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
    Wire.write(0x20);  // 0x2000 soft reset
    Wire.write(0x00);
    errorCount = Wire.endTransmission();
    delay(5);  // end of reset
 
    Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
    Wire.write(0x31);  // 0x31AE read serial
    Wire.write(0xAE);
    errorCount += Wire.endTransmission();
 
    errorCount += ((6u == Wire.requestFrom(MFM_SFM_3300D_I2C_ADDRESS, 6)) ? 0u : 1u);
    if (errorCount == 0u) {
        u_int32_t sn_expi = 0;
        sn_expi = Wire.read();
        sn_expi <<= 8;
        sn_expi |= Wire.read();
        sn_expi <<= 8;
        Wire.read();  // ignore inlined crc
        sn_expi |= Wire.read();
        sn_expi <<= 8;
        sn_expi |= Wire.read();
        Wire.read();  // ignore inlined crc
        mfmSfm3300SerialNumberExpi = sn_expi;
    }
    delay(10);
    Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
    Wire.write(0x10);  // 0x1000 start measurement
    Wire.write(0x00);
    errorCount += Wire.endTransmission();
    Wire.end();
    delay(100);  // wait 100ms before having available data.
 
    if (errorCount != 0u) {
        mfmFaultCondition = true;
        mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
    }
#endif
 
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
 
    /*
    Init sequence for Honeywell Zephyr mass flow sensor:
    1st read operation: the sensor will send 0x0000
    2nd read operation: the sensor will send the first part of the serial number
    3rd read operation: the sensor will send the second part of the serial number
    Subsequent read operations: the sensor will send calibrated mass air flow values with two
    leading 0
    */
    Wire.begin();
    Wire.beginTransmission(MFM_HONEYWELL_HAF_I2C_ADDRESS);
    Wire.write(0x02);  // Force reset
    uint8_t txOk = Wire.endTransmission();
    Wire.end();
    delay(30);
 
    u_int32_t sn = 0;
    Wire.begin();
    Wire.beginTransmission(MFM_HONEYWELL_HAF_I2C_ADDRESS);
    uint8_t rxcount = Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
    sn = Wire.read();
    sn <<= 8;
    sn |= Wire.read();  // first transmission is serial number register 0
    sn <<= 8;
    delay(2);  // if you do not wait, sensor will send again register 0
    rxcount += Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
    sn |= Wire.read();
    sn <<= 8;
    sn |= Wire.read();  // second transmission is serial number register 1
 
    if ((txOk != 0u) || (rxcount != 4u)) {  // If transmission failed
        mfmFaultCondition = true;
        mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
    } else {
        mfmHoneywellHafSerialNumber = sn;
    }
    Wire.end();
 
#if MODE == MODE_MFM_TESTS
    Serial.println("Read 1");
    Serial.println(mfmLastData.i);
    Serial.println("fault condition:");
    Serial.println(mfmFaultCondition ? "failure" : "no failure");
#endif
    delay(100);
#endif
 
    massFlowTimer->resume();
    return !mfmFaultCondition;
}

MFM_read_airflow()

int32_t MFM_read_airflow

(

void

)

Read instant air flow.

Definition at line 555 of file mass_flow_meter.cpp.

                               {
    int32_t r;
    if (mfmFaultCondition) {
        r = MASS_FLOW_ERROR_VALUE;
    } else {
        r = mfmInspiratoryInstantAirFlow - mfmInspiratoryCalibrationOffset;
    }
    return r;
}

MFM_read_milliliters()

int32_t MFM_read_milliliters

(

bool

reset_after_read

)

Get the number of milliliters since last reset.

Parameters

reset_after_read

If true, performs the volume reset in the same atomic operation

Returns

Volume of air that went through sensor since last reset in mL

Definition at line 637 of file mass_flow_meter.cpp.

                                                    {
    int32_t result = MASS_FLOW_ERROR_VALUE;
 
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF || MASS_FLOW_METER_SENSOR == MFM_SFM3019
    // period is MASS_FLOW_PERIOD / 10000  (100 µs prescaler)
    result = mfmFaultCondition
                 ? MASS_FLOW_ERROR_VALUE
                 : ((mfmInspiratoryAirVolumeSumMilliliters * MASS_FLOW_PERIOD) / (60 * 10000));
#endif
 
    if (reset_after_read) {
        MFM_reset();
    }
 
    return result;
}

MFM_read_serial_number()

uint32_t MFM_read_serial_number

(

void

)

Get the serial number of the inspiratory flow meter.

Returns

The serial number, or 0 if before init or if init failed

Definition at line 581 of file mass_flow_meter.cpp.

                                      {
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
    return mfmHoneywellHafSerialNumber;
#elif MASS_FLOW_METER_SENSOR == MFM_SFM3019
    return mfmSfm3019SerialNumber;
#endif
    return 0;
}

MFM_reset()

void MFM_reset

(

void

)

Reset the volume counter.

Definition at line 576 of file mass_flow_meter.cpp.

{ mfmInspiratoryAirVolumeSumMilliliters = 0; }

MFM_Timer_Callback()

void MFM_Timer_Callback

(

HardwareTimer *

)

Definition at line 102 of file mass_flow_meter.cpp.

{
#if MODE == MODE_MFM_TESTS
    // cppcheck-suppress misra-c2012-12.3
    digitalWrite(PIN_LED_START, HIGH);
    // it takes typically 350 µs to read the value.
#endif
    if (MFM_force_release_I2C != static_cast<uint16_t>(MFM_FORCE_RELEASE_I2C_TRUE)) {
        if (!mfmFaultCondition) {
#if MASS_FLOW_METER_SENSOR == MFM_SFM3019
            Wire.begin();
            uint8_t readCountbis = Wire.requestFrom(MFM_SFM3019_I2C_ADDRESS, 3);
            mfmLastData.c[1] = Wire.read();
            mfmLastData.c[0] = Wire.read();
            Wire.end();
            // Hardware reset if not able to read two bytes.
            if (readCountbis != 3u) {
                mfmFaultCondition = true;
                mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
                mfmInspiratoryAirVolumeSumMilliliters = 1000000000;  // 1e9
            }
            mfmInspiratoryLastValueFixedFloat = (1000 * (mfmLastData.si + 24576)) / 170;
 
#endif
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
 
            // begin() and end() everytime you read... the lib never free buffers if you don't do
            // this.
            Wire.begin();
            uint8_t readCount = Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
            mfmLastData.c[0] = Wire.read();
            mfmLastData.c[1] = Wire.read();
            // Wire.endTransmission() send a new write order followed by a stop. Useless and the
            // sensor often nack it.
            Wire.end();
 
            // Hardware reset if not able to read two bytes.
            if (readCount != 2u) {
                mfmFaultCondition = true;
                mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
                mfmInspiratoryAirVolumeSumMilliliters = 1000000000;  // 1e9
            }
 
            mfmInspiratoryLastValue = (uint32_t)(mfmLastData.c[1] & 0xFFu);
            mfmInspiratoryLastValue |= (((uint32_t)mfmLastData.c[0]) << 8) & 0x0000FF00u;
 
            // Theorical formula: Flow(slpm) = 200*((rawvalue/16384)-0.1)/0.8
            // float implementation, 1 liter per minute unit
            // mfmLastValueFloat =
            //    MFM_RANGE * (((uint32_t)mfmInspiratoryLastValue / 16384.0) - 0.1) / 0.8;
            // (Output value in SLPM)
 
            // fixed float implementation, 1 milliliter per minute unit
            mfmInspiratoryLastValueFixedFloat =
                (((10 * mfmInspiratoryLastValue) - 16384) * 1526) / 1000;
 
            // 100 value per second, 100 slpm during 10 minutes: sum will be 1.2e9. it fits in a
            // int32 int32 max with milliliters = 2e6 liters.
 
#endif
 
#if MASS_FLOW_METER_SENSOR == MFM_SFM3019 || MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
            // The sensor (100 SPLM version anyway) tends to output spurrious values located at
            // around 500 SLM, which are obviously not correct. Let's filter them out based on the
            // range of the sensor + 10%.
            if (mfmInspiratoryLastValueFixedFloat < (MFM_RANGE * 1100)) {
                mfmInspiratoryInstantAirFlow = mfmInspiratoryLastValueFixedFloat;
                if (mfmInspiratoryLastValueFixedFloat > 500) {  // less than 0.5 SPLM is noise
                    mfmInspiratoryAirVolumeSumMilliliters +=
                        (mfmInspiratoryLastValueFixedFloat - mfmInspiratoryCalibrationOffset);
                }
                // also fill the last values table used to compute average, and update the index
                if (mfmInspiratoryInstantAirFlowRecord) {
                    mfmInspiratoryInstantAirFlowLastValues
                        [mfmInspiratoryInstantAirFlowLastValuesIndex] =
                            mfmInspiratoryLastValueFixedFloat;
                    mfmInspiratoryInstantAirFlowLastValuesIndex++;
                    if (MFM_MEAN_SAMPLES == mfmInspiratoryInstantAirFlowLastValuesIndex) {
                        mfmInspiratoryInstantAirFlowLastValuesIndex = 0;
                        // table full, stops
                        mfmInspiratoryInstantAirFlowRecord = false;
                    }
                }
            }
#endif
 
#if MASS_FLOW_METER_SENSOR_EXPI == MFM_SFM_3300D
            // begin() and end() everytime you read... the lib never free buffers if you don't do
            // this.
            Wire.begin();
            // do not request crc, only two bytes
            uint8_t readCountExpi = Wire.requestFrom(MFM_SFM_3300D_I2C_ADDRESS, 2);
            mfmLastData.c[1] = Wire.read();
            mfmLastData.c[0] = Wire.read();
            Wire.end();
 
            // conversion in milliter per minute flow: ((int32_t)(mfmLastData.i) - 32768) * 1000 /
            // 120 but 1000/120 = 8.333. So  *8 and *1/3
            mfmExpiratoryLastValueFixedFloat =
                (((int32_t)(mfmLastData.i) - 32768) * 8) + (((int32_t)(mfmLastData.i) - 32768) / 3);
 
            if (readCountExpi != 2u) {
                mfmExpiSFM3300FailCounter++;
                // sfm 3300d needs 100ms after start of measurement before sending data.
                // in case of bus failure, mfmFaultCondition is already true at this point
                if ((mfmExpiSFM3300FailCounter > 12u) || mfmFaultCondition) {
                    mfmFaultCondition = true;
                    mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
                    mfmExpiratoryAirVolumeSumMilliliters = 1000000000;  // 1e9
                }
            } else {
                // valid data
                mfmExpiratoryInstantAirFlow = mfmExpiratoryLastValueFixedFloat;
                if ((mfmExpiratoryLastValueFixedFloat > 500)
                    || (mfmExpiratoryLastValueFixedFloat < -500)) {  // less than 0.5 SPLM is noise
                    mfmExpiratoryAirVolumeSumMilliliters +=
                        (mfmExpiratoryLastValueFixedFloat - mfmExpiratoryCalibrationOffset);
                }
            }
 
#endif
        } else {
            if (mfmResetStateMachine == MFM_WAIT_RESET_PERIODS) {
                // Reset attempt
                // I2C sensors
                Wire.flush();
                Wire.end();
 
                // Set power off (available since hw3)
                digitalWrite(MFM_POWER_CONTROL, MFM_POWER_OFF);
                // also set SDA and SCL to 0 to avoid sensor to be powered by I2C bus.
                pinMode(PIN_I2C_SDA, OUTPUT);
                pinMode(PIN_I2C_SCL, OUTPUT);
                digitalWrite(PIN_I2C_SCL, LOW);
                __NOP();
                digitalWrite(PIN_I2C_SDA, LOW);
            }
 
            mfmResetStateMachine--;
 
            // x period before end of reset cycle, power on again
            if (mfmResetStateMachine == MFM_WAIT_WARMUP_PERIODS) {
                // Set power on (available since hw v3)
                digitalWrite(MFM_POWER_CONTROL, MFM_POWER_ON);
                pinMode(PIN_I2C_SDA, INPUT);
                pinMode(PIN_I2C_SCL, INPUT);
            }
 
#if MASS_FLOW_METER_SENSOR == MFM_SFM3019
            if (mfmResetStateMachine == MFM_WAIT_SOFTRESET_PERIODS) {
                // start air continuous measurement
                Wire.begin();
                Wire.beginTransmission(MFM_SFM3019_I2C_ADDRESS);
                Wire.write(0x36);
                Wire.write(0x08);
                mfmFaultCondition = (0 != Wire.endTransmission()) || mfmFaultCondition;
                Wire.end();
            }
 
#endif
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
            if (mfmResetStateMachine == MFM_WAIT_SOFTRESET_PERIODS) {
                Wire.begin();
                Wire.beginTransmission(MFM_HONEYWELL_HAF_I2C_ADDRESS);
                Wire.write(0x02);                         // Force reset
                uint8_t status = Wire.endTransmission();  // actually send the data
                Wire.end();
                if (status != 0u) {  // still a problem
                    mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
                }
            }
            if (mfmResetStateMachine == MFM_WAIT_READSERIALR1_PERIODS) {
                Wire.begin();
                // read first serial number register
                uint8_t rxcount = Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
                Wire.end();
                if (rxcount != 2u) {  // still a problem
                    mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
                }
            }
#endif
 
            if (mfmResetStateMachine == 0) {
                mfmFaultCondition = false;
                // MFM_WAIT_RESET_PERIODS cycles later, try again to init the sensor
 
#if MASS_FLOW_METER_SENSOR == MFM_HONEYWELL_HAF
                Wire.begin();
                // read second serial number register
                uint8_t rxcount = Wire.requestFrom(MFM_HONEYWELL_HAF_I2C_ADDRESS, 2);
                Wire.end();
                mfmFaultCondition = (rxcount != 2u) || mfmFaultCondition;
#endif
 
#if MASS_FLOW_METER_SENSOR_EXPI == MFM_SFM_3300D
                Wire.begin();
                Wire.beginTransmission(MFM_SFM_3300D_I2C_ADDRESS);
                Wire.write(0x10);
                Wire.write(0x00);
                mfmFaultCondition = (0 != Wire.endTransmission()) || mfmFaultCondition;
                mfmExpiSFM3300FailCounter = 0;
                Wire.end();
#endif
 
                if (mfmFaultCondition) {
                    mfmResetStateMachine = MFM_WAIT_RESET_PERIODS;
                }
            }
        }
    }
#if MODE == MODE_MFM_TESTS
    digitalWrite(PIN_LED_START, LOW);
    digitalWrite(PIN_LED_GREEN, mfmFaultCondition ? HIGH : LOW);
#endif
}

Variable Documentation

c

unsigned char c[2]

Definition at line 93 of file mass_flow_meter.cpp.

i

uint16_t i

Definition at line 91 of file mass_flow_meter.cpp.

massFlowTimer

HardwareTimer* massFlowTimer = NULL

Definition at line 48 of file mass_flow_meter.cpp.

MFM_force_release_I2C

volatile uint16_t MFM_force_release_I2C = MFM_FORCE_RELEASE_I2C_FALSE

Definition at line 32 of file mass_flow_meter.cpp.

mfmExpiratoryAirVolumeSumMilliliters

volatile int32_t mfmExpiratoryAirVolumeSumMilliliters = 0

Definition at line 61 of file mass_flow_meter.cpp.

mfmExpiratoryCalibrationOffset

volatile int32_t mfmExpiratoryCalibrationOffset = 0

Definition at line 60 of file mass_flow_meter.cpp.

mfmExpiratoryInstantAirFlow

volatile int32_t mfmExpiratoryInstantAirFlow = 0

Definition at line 63 of file mass_flow_meter.cpp.

mfmExpiratoryLastValueFixedFloat

volatile int32_t mfmExpiratoryLastValueFixedFloat = 0

Definition at line 75 of file mass_flow_meter.cpp.

mfmExpiratorySensorDetected

volatile int32_t mfmExpiratorySensorDetected = 0

Definition at line 62 of file mass_flow_meter.cpp.

mfmExpiSFM3300FailCounter

uint16_t mfmExpiSFM3300FailCounter = 0

Definition at line 87 of file mass_flow_meter.cpp.

mfmFaultCondition

volatile bool mfmFaultCondition = false

Definition at line 50 of file mass_flow_meter.cpp.

mfmHoneywellHafSerialNumber

uint32_t mfmHoneywellHafSerialNumber = 0

Definition at line 44 of file mass_flow_meter.cpp.

mfmInspiratoryAirVolumeSumMilliliters

volatile int32_t mfmInspiratoryAirVolumeSumMilliliters = 0

Definition at line 56 of file mass_flow_meter.cpp.

mfmInspiratoryCalibrationOffset

volatile int32_t mfmInspiratoryCalibrationOffset = 0

Definition at line 55 of file mass_flow_meter.cpp.

mfmInspiratoryInstantAirFlow

volatile int32_t mfmInspiratoryInstantAirFlow = 0

Definition at line 58 of file mass_flow_meter.cpp.

mfmInspiratoryInstantAirFlowLastValues

volatile int32_t mfmInspiratoryInstantAirFlowLastValues[MFM_MEAN_SAMPLES]

Definition at line 68 of file mass_flow_meter.cpp.

mfmInspiratoryInstantAirFlowLastValuesIndex

volatile int16_t mfmInspiratoryInstantAirFlowLastValuesIndex = 0

Definition at line 70 of file mass_flow_meter.cpp.

mfmInspiratoryInstantAirFlowRecord

volatile bool mfmInspiratoryInstantAirFlowRecord = false

Definition at line 67 of file mass_flow_meter.cpp.

mfmInspiratoryLastValue

int32_t mfmInspiratoryLastValue = 0

Definition at line 72 of file mass_flow_meter.cpp.

mfmInspiratoryLastValueFixedFloat

volatile int32_t mfmInspiratoryLastValueFixedFloat = 0

Definition at line 73 of file mass_flow_meter.cpp.

mfmInspiratorySensorDetected

volatile int32_t mfmInspiratorySensorDetected = 0

Definition at line 57 of file mass_flow_meter.cpp.

union { ... } mfmLastData

mfmResetStateMachine

int32_t mfmResetStateMachine = MFM_WAIT_RESET_PERIODS

Definition at line 85 of file mass_flow_meter.cpp.

mfmSfm3019SerialNumber

uint32_t mfmSfm3019SerialNumber = 0

Definition at line 47 of file mass_flow_meter.cpp.

mfmSfm3300SerialNumberExpi

uint32_t mfmSfm3300SerialNumberExpi = 0

Definition at line 46 of file mass_flow_meter.cpp.

si

int16_t si

Definition at line 92 of file mass_flow_meter.cpp.