ADXL362.h File Reference

All code for the ADXL362 accelerometer. More...

#include <stdint.h>
#include <stdbool.h>

Go to the source code of this file.

Typedefs
typedef enum adxl_range	ADXL_Range_t
typedef enum adxl_odr	ADXL_ODR_t

Enumerations
enum	adxl_range { ADXL_RANGE_2G, ADXL_RANGE_4G, ADXL_RANGE_8G }
enum	adxl_odr {   ADXL_ODR_12_5_HZ, ADXL_ODR_25_HZ, ADXL_ODR_50_HZ, ADXL_ODR_100_HZ,   ADXL_ODR_200_HZ, ADXL_ODR_400_HZ }

Functions
void	initADXL (void)
	Initialize the accelerometer. More...
void	ADXL_setTriggered (bool triggered)
	Setter for the ADXL_triggered variable. More...
bool	ADXL_getTriggered (void)
	Getter for the ADXL_triggered variable. More...
void	ADXL_ackInterrupt (void)
	Acknowledge the interrupt from the accelerometer. More...
uint16_t	ADXL_getCounter (void)
	Getter for the ADXL_triggercounter variable. More...
void	ADXL_clearCounter (void)
	Method to set the ADXL_triggercounter variable back to zero. More...
void	ADXL_enableSPI (bool enabled)
	Enable or disable the SPI pins and USART0/1 clock and peripheral to the accelerometer. More...
void	ADXL_enableMeasure (bool enabled)
	Enable or disable measurement mode. More...
void	ADXL_configRange (ADXL_Range_t givenRange)
	Configure the measurement range and store the selected one in a global variable for later (internal) use. More...
void	ADXL_configODR (ADXL_ODR_t givenODR)
	Configure the Output Data Rate (ODR). More...
void	ADXL_configActivity (uint8_t gThreshold)
	Configure the accelerometer to work in (referenced) activity threshold mode. More...
void	ADXL_readValues (void)
	Read and display "g" values forever with a 100ms interval. More...
void	testADXL (void)
	This method goes through all of the ODR settings to see the influence they have on power usage. The measurement range is the default one (+-2g). More...

Detailed Description

All code for the ADXL362 accelerometer.

Version

3.1

Author

Brecht Van Eeckhoudt

---

License

Copyright (C) 2019 - Brecht Van Eeckhoudt

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

A copy of the GNU General Public License can be found in the LICENSE file along with this source code.

Some methods use code obtained from examples from Silicon Labs' GitHub. These sections are licensed under the Silabs License Agreement. See the file "Silabs_License_Agreement.txt" for details. Before using this software for any purpose, you must agree to the terms of that agreement.

Definition in file ADXL362.h.

Typedef Documentation

ADXL_ODR_t

typedef enum adxl_odr ADXL_ODR_t

Enum type for the ODR

ADXL_Range_t

typedef enum adxl_range ADXL_Range_t

Enum type for the measurement range

Enumeration Type Documentation

adxl_odr

enum adxl_odr

Enum type for the ODR

Enumerator
ADXL_ODR_12_5_HZ
ADXL_ODR_25_HZ
ADXL_ODR_50_HZ
ADXL_ODR_100_HZ
ADXL_ODR_200_HZ
ADXL_ODR_400_HZ

Definition at line 55 of file ADXL362.h.

{
    ADXL_ODR_12_5_HZ, /* 12.5 Hz */
    ADXL_ODR_25_HZ,   /* 25 Hz */
    ADXL_ODR_50_HZ,   /* 50 Hz */
    ADXL_ODR_100_HZ,  /* 100 Hz (reset default) */
    ADXL_ODR_200_HZ,  /* 200 Hz */
    ADXL_ODR_400_HZ   /* 400 Hz */
} ADXL_ODR_t;

adxl_range

enum adxl_range

Enum type for the measurement range

Enumerator
ADXL_RANGE_2G
ADXL_RANGE_4G
ADXL_RANGE_8G

Definition at line 47 of file ADXL362.h.

{
    ADXL_RANGE_2G, /* +- 2g (reset default) */
    ADXL_RANGE_4G, /* +- 4g */
    ADXL_RANGE_8G  /* +- 8g */
} ADXL_Range_t;

Function Documentation

ADXL_ackInterrupt()

void ADXL_ackInterrupt

(

void

)

Acknowledge the interrupt from the accelerometer.

Read a certain register (necessary if the accelerometer is not in linked-loop mode) and clear the variable.

Definition at line 230 of file ADXL362.c.

{
    readADXL(ADXL_REG_STATUS);
    ADXL_triggered = false;
}

ADXL_clearCounter()

void ADXL_clearCounter

(

void

)

Method to set the ADXL_triggercounter variable back to zero.

Definition at line 188 of file ADXL362.c.

{
    ADXL_triggercounter = 0;
}

ADXL_configActivity()

void ADXL_configActivity

(

uint8_t

gThreshold

)

Configure the accelerometer to work in (referenced) activity threshold mode.

Route activity detector to INT1 pin using INTMAP1, isolate bits and write settings to both threshold registers.

Referenced means that during the initialization a reference acceleration gets measured (like for example 1 g on a certain axis) and stored internally. This value always gets internally subtracted from a measured acceleration value to calculate the final value and check if it exceeds the set threshold:

• ABS(acceleration - reference) > threshold

Parameters

[in]

gThreshold

Threshold [g].

Definition at line 468 of file ADXL362.c.

{
    /* Map activity detector to INT1 pin  */
    writeADXL(ADXL_REG_INTMAP1, 0b00010000); /* Bit 4 selects activity detector */

    /* Enable referenced activity threshold mode (last two bits) */
    writeADXL(ADXL_REG_ACT_INACT_CTL, 0b00000011);

    /* Convert g value to "codes"
     *   THRESH_ACT [codes] = Threshold Value [g] × Scale Factor [LSB per g] */
    uint8_t threshold;

    if (range == ADXL_RANGE_2G) threshold = gThreshold * 1000;
    else if (range == ADXL_RANGE_4G) threshold = gThreshold * 500;
    else if (range == ADXL_RANGE_8G) threshold = gThreshold * 250;
    else
    {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbcrit("Range wrong, can't set gThreshold!");
#endif /* DEBUG_DBPRINT */

        error(26);

        /* Exit function */
        return;
    }

    /* Isolate bits using masks and shifting */
    uint8_t low  = (threshold & 0b0011111111);
    uint8_t high = (threshold & 0b1100000000) >> 8;

    /* Set threshold register values (total: 11bit unsigned) */
    writeADXL(ADXL_REG_THRESH_ACT_L, low);  /* 7:0 bits used */
    writeADXL(ADXL_REG_THRESH_ACT_H, high); /* 2:0 bits used */

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
    dbinfoInt("ADXL362: Activity configured: ", gThreshold, "g");
#endif /* DEBUG_DBPRINT */

}

ADXL_configODR()

void ADXL_configODR

(

ADXL_ODR_t

givenODR

)

Configure the Output Data Rate (ODR).

Parameters

[in]

givenODR

The selected ODR.

Definition at line 411 of file ADXL362.c.

{
    /* Get value in register */
    uint8_t reg = readADXL(ADXL_REG_FILTER_CTL);

    /* AND with mask to keep the bits we don't want to change */
    reg &= 0b11111000;

    /* Set ODR (OR with new setting bits, last three bits) */
    if (givenODR == ADXL_ODR_12_5_HZ) writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000000));
    else if (givenODR == ADXL_ODR_25_HZ) writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000001));
    else if (givenODR == ADXL_ODR_50_HZ) writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000010));
    else if (givenODR == ADXL_ODR_100_HZ) writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000011));
    else if (givenODR == ADXL_ODR_200_HZ) writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000100));
    else if (givenODR == ADXL_ODR_400_HZ) writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000101));
    else
    {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbcrit("Non-existing ODR selected!");
#endif /* DEBUG_DBPRINT */

        error(25);

        /* Exit function */
        return;
    }

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
    if (givenODR == ADXL_ODR_12_5_HZ) dbinfo("ADXL362: ODR set at 12.5 Hz");
    else if (givenODR == ADXL_ODR_25_HZ) dbinfo("ADXL362: ODR set at 25 Hz");
    else if (givenODR == ADXL_ODR_50_HZ) dbinfo("ADXL362: ODR set at 50 Hz");
    else if (givenODR == ADXL_ODR_100_HZ) dbinfo("ADXL362: ODR set at 100 Hz");
    else if (givenODR == ADXL_ODR_200_HZ) dbinfo("ADXL362: ODR set at 200 Hz");
    else if (givenODR == ADXL_ODR_400_HZ) dbinfo("ADXL362: ODR set at 400 Hz");
#endif /* DEBUG_DBPRINT */

}

ADXL_configRange()

void ADXL_configRange

(

ADXL_Range_t

givenRange

)

Configure the measurement range and store the selected one in a global variable for later (internal) use.

When a range of, for example "2g" is selected, the real range is "+-2g".

Parameters

[in]

givenRange

The selected range.

Definition at line 358 of file ADXL362.c.

{
    /* Get value in register */
    uint8_t reg = readADXL(ADXL_REG_FILTER_CTL);

    /* AND with mask to keep the bits we don't want to change */
    reg &= 0b00111111;

    /* Set measurement range (OR with new setting bits, first two bits) */
    if (givenRange == ADXL_RANGE_2G)
    {
        writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b00000000));
        range = ADXL_RANGE_2G;
    }
    else if (givenRange == ADXL_RANGE_4G)
    {
        writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b01000000));
        range = ADXL_RANGE_4G;
    }
    else if (givenRange == ADXL_RANGE_8G)
    {
        writeADXL(ADXL_REG_FILTER_CTL, (reg | 0b10000000));
        range = ADXL_RANGE_8G;
    }
    else
    {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbcrit("Non-existing range selected!");
#endif /* DEBUG_DBPRINT */

        error(24);

        /* Exit function */
        return;
    }

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
    if (range == ADXL_RANGE_2G) dbinfo("ADXL362: Measurement mode +- 2g selected");
    else if (range == ADXL_RANGE_4G) dbinfo("ADXL362: Measurement mode +- 4g selected");
    else if (range == ADXL_RANGE_8G) dbinfo("ADXL362: Measurement mode +- 8g selected");
#endif /* DEBUG_DBPRINT */

}

ADXL_enableMeasure()

void ADXL_enableMeasure

(

bool

enabled

)

Enable or disable measurement mode.

Parameters

[in]

enabled

true - Enable measurement mode. false - Disable measurement mode (standby).

Definition at line 310 of file ADXL362.c.

{
    if (enabled)
    {
        /* Get value in register */
        uint8_t reg = readADXL(ADXL_REG_POWER_CTL);

        /* AND with mask to keep the bits we don't want to change */
        reg &= 0b11111100;

        /* Enable measurements (OR with new setting bits) */
        writeADXL(ADXL_REG_POWER_CTL, reg | 0b00000010); /* Last 2 bits are measurement mode */

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbinfo("ADXL362: Measurement enabled");
#endif /* DEBUG_DBPRINT */

    }
    else
    {
        /* Get value in register */
        uint8_t reg = readADXL(ADXL_REG_POWER_CTL);

        /* AND with mask to keep the bits we don't want to change */
        reg &= 0b11111100;

        /* Disable measurements (OR with new setting bits) */
        writeADXL(ADXL_REG_POWER_CTL, reg | 0b00000000); /* Last 2 bits are measurement mode */

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbinfo("ADXL362: Measurement disabled (standby)");
#endif /* DEBUG_DBPRINT */

    }
}

ADXL_enableSPI()

void ADXL_enableSPI

(

bool

enabled

)

Enable or disable the SPI pins and USART0/1 clock and peripheral to the accelerometer.

Parameters

[in]

enabled

true - Enable the SPI pins and USART0/1 clock and peripheral to the accelerometer. false - Disable the SPI pins and USART0/1 clock and peripheral to the accelerometer.

Definition at line 245 of file ADXL362.c.

{
    if (enabled)
    {
        /* Enable USART clock and peripheral */
        if (ADXL_SPI == USART0) CMU_ClockEnable(cmuClock_USART0, true);
        else if (ADXL_SPI == USART1) CMU_ClockEnable(cmuClock_USART1, true);
        else
        {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
            dbcrit("Wrong peripheral selected!");
#endif /* DEBUG_DBPRINT */

            error(22);

            /* Exit function */
            return;
        }

        USART_Enable(ADXL_SPI, usartEnable);

        /* In the case of gpioModePushPull", the last argument directly sets the pin state */
        GPIO_PinModeSet(ADXL_CLK_PORT, ADXL_CLK_PIN, gpioModePushPull, 0);   /* US0_CLK is push pull */
        GPIO_PinModeSet(ADXL_NCS_PORT, ADXL_NCS_PIN, gpioModePushPull, 1);   /* US0_CS is push pull */
        GPIO_PinModeSet(ADXL_MOSI_PORT, ADXL_MOSI_PIN, gpioModePushPull, 1); /* US0_TX (MOSI) is push pull */
        GPIO_PinModeSet(ADXL_MISO_PORT, ADXL_MISO_PIN, gpioModeInput, 1);    /* US0_RX (MISO) is input */
    }
    else
    {
        /* Disable USART clock and peripheral */
        if (ADXL_SPI == USART0) CMU_ClockEnable(cmuClock_USART0, false);
        else if (ADXL_SPI == USART1) CMU_ClockEnable(cmuClock_USART1, false);
        else
        {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
            dbcrit("Wrong peripheral selected!");
#endif /* DEBUG_DBPRINT */

            error(23);

            /* Exit function */
            return;
        }

        USART_Enable(ADXL_SPI, usartDisable);

        /* gpioModeDisabled: Pull-up if DOUT is set. */
        GPIO_PinModeSet(ADXL_CLK_PORT, ADXL_CLK_PIN, gpioModeDisabled, 0);
        GPIO_PinModeSet(ADXL_NCS_PORT, ADXL_NCS_PIN, gpioModeDisabled, 1);
        GPIO_PinModeSet(ADXL_MOSI_PORT, ADXL_MOSI_PIN, gpioModeDisabled, 1);
        GPIO_PinModeSet(ADXL_MISO_PORT, ADXL_MISO_PIN, gpioModeDisabled, 1);
    }
}

ADXL_getCounter()

uint16_t ADXL_getCounter

(

void

)

Getter for the ADXL_triggercounter variable.

Returns

The value of ADXL_triggercounter.

Definition at line 178 of file ADXL362.c.

{
    return (ADXL_triggercounter);
}

ADXL_getTriggered()

bool ADXL_getTriggered

(

void

)

Getter for the ADXL_triggered variable.

Returns

The value of ADXL_triggered.

Definition at line 216 of file ADXL362.c.

{
    return (ADXL_triggered);
}

ADXL_readValues()

void ADXL_readValues

(

void

)

Read and display "g" values forever with a 100ms interval.

Definition at line 515 of file ADXL362.c.

{
    uint32_t counter = 0;

    /* Enable measurement mode */
    ADXL_enableMeasure(true);

    /* Infinite loop */
    while (1)
    {
        led(true); /* Enable LED */

        readADXL_XYZDATA(); /* Read XYZ sensor data */

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        /* Print XYZ sensor data */
        dbprint("\r[");
        dbprintInt(counter);
        dbprint("] X: ");
        dbprintInt(convertGRangeToGValue(XYZDATA[0]));
        dbprint(" mg | Y: ");
        dbprintInt(convertGRangeToGValue(XYZDATA[1]));
        dbprint(" mg | Z: ");
        dbprintInt(convertGRangeToGValue(XYZDATA[2]));
        dbprint(" mg       "); /* Extra spacing is to overwrite other data if it's remaining (see \r) */
#endif /* DEBUG_DBPRINT */

        led(false); /* Disable LED */

        counter++;

        delay(100);
    }
}

ADXL_setTriggered()

void ADXL_setTriggered

(

bool

triggered

)

Setter for the ADXL_triggered variable.

Parameters

[in]

triggered

true - Set ADXL_triggered to true. false - Set ADXL_triggered to false.

Definition at line 202 of file ADXL362.c.

{
    ADXL_triggered = triggered;
    ADXL_triggercounter++;
}

initADXL()

void initADXL

(

void

)

Initialize the accelerometer.

This method calls all the other internal necessary functions. Clock enable functionality is gathered here instead of in lower (static) functions.

Definition at line 132 of file ADXL362.c.

{
    /* Enable necessary clocks (just in case) */
    CMU_ClockEnable(cmuClock_HFPER, true); /* GPIO and USART0/1 are High Frequency Peripherals */
    CMU_ClockEnable(cmuClock_GPIO, true);

    /* Initialize and power VDD pin */
    powerADXL(true);

    /* Power-up delay of 40 ms */
    delay(40);

    /* Enable necessary clock (just in case) */
    if (ADXL_SPI == USART0) CMU_ClockEnable(cmuClock_USART0, true);
    else if (ADXL_SPI == USART1) CMU_ClockEnable(cmuClock_USART1, true);
    else
    {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbcrit("Wrong peripheral selected!");
#endif /* DEBUG_DBPRINT */

        /* Disable power to the VDD pin */
        powerADXL(false);

        error(21);

        /* Exit function */
        return;
    }

    /* Initialize USART0/1 as SPI slave (also initialize CS pin) */
    initADXL_SPI();

    /* Soft reset ADXL handler */
    resetHandlerADXL();
}

testADXL()

void testADXL

(

void

)

This method goes through all of the ODR settings to see the influence they have on power usage. The measurement range is the default one (+-2g).

To get the "correct" currents the delay method puts the MCU to EM2/3 sleep and the SPI lines are disabled. The order of the test is:

• Wait 5 seconds
• Soft reset the accelerometer
• One second in "standby" mode
• Enable "measurement" mode
• One second in ODR 12.5 Hz
• One second in ODR 25 Hz
• One second in ODR 50 Hz
• One second in ODR 100 Hz
• One second in ODR 200 Hz
• One second in ODR 400 Hz
• Soft reset the accelerometer

Definition at line 571 of file ADXL362.c.

{
    delay(5000);

    /* Soft reset ADXL */
    softResetADXL();

    /* Standby */
    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* ODR 12,5Hz */
    writeADXL(ADXL_REG_FILTER_CTL, 0b00010000); /* last 3 bits are ODR */

    /* Enable measurements */
    writeADXL(ADXL_REG_POWER_CTL, 0b00000010); /* last 2 bits are measurement mode */

    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* ODR 25Hz */
    writeADXL(ADXL_REG_FILTER_CTL, 0b00010001); /* last 3 bits are ODR */

    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* ODR 50Hz */
    writeADXL(ADXL_REG_FILTER_CTL, 0b00010010); /* last 3 bits are ODR */

    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* ODR 100Hz (default) */
    writeADXL(ADXL_REG_FILTER_CTL, 0b00010011); /* last 3 bits are ODR */

    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* ODR 200Hz */
    writeADXL(ADXL_REG_FILTER_CTL, 0b00010100); /* last 3 bits are ODR */

    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* ODR 400Hz */
    writeADXL(ADXL_REG_FILTER_CTL, 0b00010101); /* last 3 bits are ODR */

    ADXL_enableSPI(false); /* Disable SPI functionality */
    delay(1000);
    ADXL_enableSPI(true);  /* Enable SPI functionality */

    /* Soft reset ADXL */
    softResetADXL();
}