PowerSupplyHardware.cpp

#include "PowerSupplyHardware.h"

PowerSupplyHardware::PowerSupplyHardware() :
  control_knob(ENCODER_A_PIN, ENCODER_B_PIN),
  voltage_output_1s(DIGIT1_DATA_PIN, DIGIT1_CLOCK_PIN, DIGIT1_LATCH_PIN),
  voltage_output_10s(DIGIT2_DATA_PIN, DIGIT2_CLOCK_PIN, DIGIT2_LATCH_PIN),
  voltage_adjuster(DIGIPOT_CS_PIN, POT_RESISTANCE, POT_TAPS)
{

  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(BLUE_LED_PIN, OUTPUT);

  pinMode(BUTTON_PIN, INPUT);

}

static PowerSupplyHardware &PowerSupplyHardware::GetInstance(){
  static PowerSupplyHardware instance;
  return instance;
}

bool PowerSupplyHardware::button_state(){
  return digitalRead(BUTTON_PIN);
}

void PowerSupplyHardware::set_knob_color(bool r, bool g, bool b){
  digitalWrite(RED_LED_PIN, !r);
  digitalWrite(GREEN_LED_PIN, !g);
  digitalWrite(BLUE_LED_PIN, !b);
}

long PowerSupplyHardware::get_constrained_knob_pos(){
  // Prevent knob from setting to value that cannot be set on the digipot
  // TODO: possibly remove
  long knob_pos = control_knob.read();
  long adjusted_knob_pos = constrain(knob_pos, 0, POT_TAPS * ENC_PULSES_PER_TAP);
  if(knob_pos != adjusted_knob_pos){
    control_knob.write(adjusted_knob_pos);
  }
  return adjusted_knob_pos;
}

float PowerSupplyHardware::get_voltage(){
  // Return the current voltage of the power supply output
  // Measured from the voltage divider
  /*
    VCC---/\/\/\/---.---/\/\/\/---GND
            R1      |     R2
                Analog In
  */
  long R1 = 65450;
  long R2 = 21800;
  int reading = analogRead(VOLTAGE_MEASUREMENT_PIN);
  float measured_voltage = reading * 4.968 / 1023; // On a 5v scale
  float actual_voltage = measured_voltage * (R1 + R2) / R2; // Convert to 20v scale
  return actual_voltage;
}
void PowerSupplyHardware::set_voltage_raw(int taps){
  // TODO: replace with actual set voltage
  voltage_adjuster.set_raw(taps);
}

float PowerSupplyHardware::get_current(){
  int reading = analogRead(CURRENT_MEASUREMENT_PIN);
  // Sensor spec: 0.185v/A --> 5.4 A/v
  // 5.4 A/v * 5v / 1023 analog = 0.0264 A / analog
  // 0v --> -13.51 A
  const float SLOPE = 5.4;//A/v
  const float SYS_VOLTAGE = 5;//v
  const float A_TO_D_RES = 1023;
  const float CURRENT_SENSE_ZERO = 2.482;//v
  float measured_voltage = SYS_VOLTAGE / A_TO_D_RES * reading;
  return SLOPE * (measured_voltage - CURRENT_SENSE_ZERO);
}

void PowerSupplyHardware::display_two_digits(float number){
  number = round(abs(number)*10) / 10.0;
  if(number < 10){
    disp_digit(DIGIT10s, (int)number, true);
    disp_digit(DIGIT1s, (int)(number * 10) % 10, false);
  } else {
    number = round(number);
    disp_digit(DIGIT10s, ((int)number / 10) % 10, false);
    disp_digit(DIGIT1s, ((int)number) % 10, false);
  }
}

const int PowerSupplyHardware::DIGIT_1_CODES[10] = {
  0b11011110,
  0b00011000,
  0b11001101,
  0b10011101,
  0b00011011,
  0b10010111,
  0b11010111,
  0b00011100,
  0b11011111,
  0b10011111
};
const int PowerSupplyHardware::DIGIT_10_CODES[10] = {
  0b11011110,
  0b01000010,
  0b11101100,
  0b11100110,
  0b01110010,
  0b10110110,
  0b10111110,
  0b11000010,
  0b11111110,
  0b11110110
};

void PowerSupplyHardware::disp_digit(DIGIT pos, int number, bool period){
  int *codes;
  int decimal_bit; // Bit to set the period/decimal point on the digit
  Shift7Segment *shift_reg;

  if(pos == DIGIT1s){
    codes = DIGIT_1_CODES;
    decimal_bit = 5;
    shift_reg = &voltage_output_1s;
  } else if(pos == DIGIT10s){
    codes = DIGIT_10_CODES;
    decimal_bit = 0;
    shift_reg = &voltage_output_10s;
  } else {
    return; // Invalid digit selection
  }

  byte code = 0;
  if(number >= 0 && number < 10){
    code = codes[number];
  }
  if(period){
    bitWrite(code, decimal_bit, 1); // set period bit
  }
  shift_reg->disp_byte(code);
}

void PowerSupplyHardware::load_state(int eeprom_address){
  // recall last saved control value
  long saved_knob_pos;
  EEPROM.get(eeprom_address, saved_knob_pos);
  control_knob.write(saved_knob_pos);
}

void PowerSupplyHardware::save_state(int eeprom_address){
  EEPROM.put(eeprom_address, get_constrained_knob_pos());
}