Program Listing for File btn99x0_half_bridge.cpp

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#include "btn99x0_half_bridge.hpp"

using namespace btn99x0;

const ic_experimental_const_t HalfBridge::btn9970lv_typical_exp_const =
{
    3.72e-6,
    40000,
    0
};

const ic_experimental_const_t HalfBridge::btn9990lv_typical_exp_const =
{
    3.72e-6,
    50000,
    0
};

HalfBridge::HalfBridge(ic_variant_t ic_variant, io_pins_t io_pins, hw_conf_t hw_conf)
:
io_pins(io_pins),
exp_const(get_typical_experimental_constants(ic_variant)),
hw_conf(hw_conf)
{
    pinMode(io_pins.analog, INPUT);
    pinMode(io_pins.input, OUTPUT);
    pinMode(io_pins.inhibit, OUTPUT);
}

HalfBridge::~HalfBridge()
{

}

void HalfBridge::begin()
{
    delay(100);
    calculate_sense_resistor_offset_current();

    /* Initialize inhibit and input to LOW */
    set_inhibit_pin(LOW);
    digitalWrite(io_pins.input, LOW);
}

void HalfBridge::enable()
{
    set_inhibit_pin(HIGH);
}

void HalfBridge::disable()
{
    set_inhibit_pin(LOW);
}

void HalfBridge::set_pwm(uint8_t duty)
{
    analogWrite(io_pins.input, duty);
}

void HalfBridge::set_pwm_in_percentage(uint8_t duty_in_pct)
{
    if((duty_in_pct <= 100) & (duty_in_pct >= 0))
    {
        duty_in_pct = duty_in_pct*255/100;
        analogWrite(io_pins.input, duty_in_pct);
    };
}

error_t HalfBridge::set_slew_rate(slew_rate_level_t sr_level)
{
    if(LOW != inhibit_pin_value)
    {
        return INVALID_OPERATION_ERROR;
    }

    /*
    pulses the input_pin pin
    */
    delayMicroseconds(5);
    for(uint8_t i = 0; i <= ((uint8_t)sr_level + 1); i++)
    {
        digitalWrite(io_pins.input, HIGH);
        delayMicroseconds(1);
        digitalWrite(io_pins.input, LOW);
    }
    delayMicroseconds(5);

    return NO_ERROR;
}

error_t HalfBridge::get_diagnosis()
{
    if(calculate_current_at_sense_resistor_in_amps() >= fault_current_amps)
    {
        return FAULT_CURRENT_ERROR;
    }

    return NO_ERROR;
}

void HalfBridge::set_ktis(float ktis_amps_per_kelvin)
{
    exp_const.ktis_amps_per_kelvin = ktis_amps_per_kelvin;
}

void HalfBridge::set_dk(uint16_t dk)
{
    exp_const.dk = dk;
}

double HalfBridge::get_load_current_in_amps()
{
    return ((exp_const.dk)*(calculate_current_at_sense_resistor_in_amps() - exp_const.sense_current_offset_amps));
}

double HalfBridge::get_temperature_in_kelvin()
{
    if(LOW != inhibit_pin_value)
    {
        return (double)INVALID_OPERATION_ERROR;
    }

    double chip_temperature;

    digitalWrite(io_pins.input, HIGH);
    delayMicroseconds(7);

    chip_temperature = (calculate_current_at_sense_resistor_in_amps())/exp_const.ktis_amps_per_kelvin;

    return chip_temperature;
}

void HalfBridge::set_inhibit_pin(uint8_t value)
{
    inhibit_pin_value = value;
    digitalWrite(io_pins.inhibit, value);
}

double HalfBridge::calculate_current_at_sense_resistor_in_amps()
{
    double adc_volts_per_step = (hw_conf.adc_voltage_range_volts/hw_conf.adc_resolution_steps);
    double voltage_sense_resistor_volts = analogRead(io_pins.analog)*adc_volts_per_step;

    return voltage_sense_resistor_volts/hw_conf.sense_current_resistor_ohms;
}

void HalfBridge::calculate_sense_resistor_offset_current(void)
{
    enable();
    digitalWrite(io_pins.input, LOW);

    delayMicroseconds(50);
    exp_const.sense_current_offset_amps = calculate_current_at_sense_resistor_in_amps();
    delayMicroseconds(5);

    disable();
}

ic_experimental_const_t HalfBridge::get_typical_experimental_constants(ic_variant_t ic_variant)
{
    switch(ic_variant)
    {
        case IC_VARIANT_BTN9970LV:
            return btn9970lv_typical_exp_const;
        break;

        case IC_VARIANT_BTN9990LV:
            return btn9990lv_typical_exp_const;
        break;
    }
}