adc.c

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/*
 * adc.c
 *
 *  Date: 19/06/2014
 *  Author: Fernando Biazi Nascimento
 *  Copyright © 2014 Fernando Biazi Nascimento. All rights reserved.
 *
 *  License of use and copy on file license.txt
 *
 */

/*
 * ======== Standard MSP430 includes ========
 */
#include <msp430.h>

/*
 * ======== Includes ========
 */

#include "adc.h"

/*
 * ======== Constants ========
 */

/*
 * ======== Macros ========
 */

#define ADC_FLAGTEMPDONE BIT0

#define ADC_FLAGVOLTDONE BIT1

#define ADC_FLAGLUXDONE BIT2

#define ADC_LUXSENSFEEDBIT BIT1

/*
 * ======== Types ========
 */

typedef enum adc_state {
  ADC_S_IDLE, 
  ADC_S_CHARGING_T, 
  ADC_S_READING_T, 
  ADC_S_CHARGING_V, 
  ADC_S_READING_V, 
  ADC_S_CHARGING_L, 
  ADC_S_READING_L 
} adc_state;

/*
 * ======== Global Variables ========
 */

/*
 * ======== Local Variables ========
 */

adc_state adc_currentState;
UInt16 adc_temp;
clock_timeStamp adc_tempTime;
UInt16 adc_voltage;
clock_timeStamp adc_voltageTime;
UInt16 adc_lux;
clock_timeStamp adc_luxTime;
UInt8 adc_flags;

/*
 * ======== Local Functions ========
 */

/*
 * ================
 */

void adc_init() {
  adc_currentState = ADC_S_IDLE;

  adc_flags = 0;

  // turn off lux sensor feed.
  P2DIR &= ~ADC_LUXSENSFEEDBIT;
  // set output value of lux sensor feed to 1.
  P2OUT |= ADC_LUXSENSFEEDBIT;

  adc_temp = 0;
  adc_tempTime.seconds.secondsLow = 0;
  adc_tempTime.seconds.secondsHigh = 0;
  adc_tempTime.nanoSeconds = 0;
  adc_voltage = 0;
  adc_voltageTime.seconds.secondsLow = 0;
  adc_voltageTime.seconds.secondsHigh = 0;
  adc_voltageTime.nanoSeconds = 0;
  adc_lux = 0;
  adc_luxTime.seconds.secondsLow = 0;
  adc_luxTime.seconds.secondsHigh = 0;
  adc_luxTime.nanoSeconds = 0;
}

UInt16 adc_proccess() {
  switch (adc_currentState) {
  case ADC_S_IDLE:
    // clear temperature done
    adc_flags &= ~ADC_FLAGTEMPDONE;
    // prepare to read temperature
    ADC10CTL1 = INCH_10 + ADC10DIV_4; // CH10 - Temp Sensor; ADC10CLK/5
    // VR+ = VREF+ and VR- = AVSS; 64 x ADC10CLKs; ADC10 Reference on; ADC10 On/Enable;
    //       ADC10 Interrupt Enable; ADC10 Sampling Rate 0=200ksps; 1=50ksps:
    ADC10CTL0 = SREF_1 + ADC10SHT_3 + REFON + ADC10ON + ADC10IE + ADC10SR;
    adc_currentState = ADC_S_CHARGING_T; // next state
    return 10; // schedule to run again in 10ms
  case ADC_S_CHARGING_T:
    adc_currentState = ADC_S_READING_T;
    ADC10CTL0 |= ENC | ADC10SC; // ADC10 Enable Conversion; ADC10 Start Conversion
    return 5; // schedule to run again in 5ms
  case ADC_S_READING_T:
    if (!(adc_flags & ADC_FLAGTEMPDONE)) {
      return 5; // temperature not ready, new check in 5ms
    }
    // clear voltage done
    adc_flags &= ~ADC_FLAGVOLTDONE
    ;
    // prepare to read voltage
    ADC10CTL1 = INCH_11 + ADC10DIV_3; // CH11 - Voltage Sensor; ADC10CLK/4
    // VR+ = VREF+ and VR- = AVSS; 16 x ADC10CLKs; ADC10 Reference on; ADC10 On/Enable;
    //       ADC10 Interrupt Enable:
    ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE;
    adc_currentState = ADC_S_CHARGING_V; // next state
    return 10; // schedule to run again in 10ms
  case ADC_S_CHARGING_V:
    adc_currentState = ADC_S_READING_V;
    ADC10CTL0 |= ENC | ADC10SC; // ADC10 Enable Conversion; ADC10 Start Conversion
    return 5;
  case ADC_S_READING_V:
    if (!(adc_flags & ADC_FLAGVOLTDONE)) {
      return 5; // voltage not ready, new check in 5ms
    }
    // clear lux done
    adc_flags &= ~ADC_FLAGLUXDONE;
    // feed lux sensor by activating P2.1 direction to out, its value is configured to be 1 on initialization.
    P2DIR |= ADC_LUXSENSFEEDBIT;
    // prepare to read luminescence
    ADC10CTL1 = INCH_0 + ADC10DIV_4; // CH00 - Lux Sensor; ADC10CLK/5
    // VR+ = VREF+ and VR- = AVSS; 64 x ADC10CLKs; ADC10 Reference on; Reference is 2.5V; ADC10 On/Enable;
    //       ADC10 Interrupt Enable; ADC10 Sampling Rate 0=200ksps; 1=50ksps:
    ADC10CTL0 = SREF_1 + ADC10SHT_3 + REFON + REF2_5V + ADC10ON + ADC10IE
        + ADC10SR;
    adc_currentState = ADC_S_CHARGING_L; // next state
    return 10; // schedule to run again in 10ms
  case ADC_S_CHARGING_L:
    adc_currentState = ADC_S_READING_L;
    ADC10CTL0 |= ENC | ADC10SC; // ADC10 Enable Conversion; ADC10 Start Conversion
    return 5;
  case ADC_S_READING_L:
    if (!(adc_flags & ADC_FLAGLUXDONE)) {
      return 5; // illuminance not ready, new check in 5ms
    }
    // turn off lux sensor feed.
    P2DIR &= ~ADC_LUXSENSFEEDBIT;
    adc_currentState = ADC_S_IDLE;
    return 955;
  default:
    adc_currentState = ADC_S_IDLE;
    return 1;
  }
}

void adc_getTemp(UInt16 *temp, clock_timeStamp *tempTime) {
  *temp = adc_temp;
  tempTime->seconds.secondsLow = adc_tempTime.seconds.secondsLow;
  tempTime->seconds.secondsHigh = adc_tempTime.seconds.secondsHigh;
  tempTime->nanoSeconds = adc_tempTime.nanoSeconds;
}

void adc_getVolt(UInt16 *volt, clock_timeStamp *voltTime) {
  *volt = adc_voltage;
  voltTime->seconds.secondsLow = adc_voltageTime.seconds.secondsLow;
  voltTime->seconds.secondsHigh = adc_voltageTime.seconds.secondsHigh;
  voltTime->nanoSeconds = adc_voltageTime.nanoSeconds;
}

void adc_getLux(UInt16 *lux, clock_timeStamp *luxTime) {
  *lux = adc_lux;
  luxTime->seconds.secondsLow = adc_luxTime.seconds.secondsLow;
  luxTime->seconds.secondsHigh = adc_luxTime.seconds.secondsHigh;
  luxTime->nanoSeconds = adc_luxTime.nanoSeconds;
}

void ADC10_ISR() {
  switch (adc_currentState) {
  case ADC_S_READING_T:
    // °C = ((A10/1024)*1500mV)-986mV)*1/3.55mV = A10*423/1024 - 278
    //adc_temp = ((ADC10MEM - 673) * 423) >> 10;
    // Make calculations on the receiving device
    adc_temp = ADC10MEM;
    ADC10CTL0 &= ~(ADC10IE & ENC); // Disable conversion
    ADC10CTL0 = 0; // Disable ADC, some values must be cleared after ENC
    clock_getTime(&adc_tempTime);
    adc_flags |= ADC_FLAGTEMPDONE;
    break;
  case ADC_S_READING_V:
    // Measurement of AVcc/2 is in range 0 to 1023 indicating voltage from 0 to 1.5V.
    //adc_voltage = (ADC10MEM * 30 + 512) >> 10; // val * 30 / 1024 + .5
    // Make calculations on the receiving device
    adc_voltage = ADC10MEM;
    ADC10CTL0 &= ~(ADC10IE & ENC); // Disable conversion
    ADC10CTL0 = 0; // Disable ADC, some values must be cleared after ENC
    clock_getTime(&adc_voltageTime);
    adc_flags |= ADC_FLAGVOLTDONE;
    break;
  case ADC_S_READING_L:
    // Measurement range 0 to 1023: 0 to 3V on sensor; series R 470 Kohm up to Vcc
    // light sensor datasheet gives a nonlinear/large variation scale.
    // Dark: 20Mohm; 10lux: 20Kohm to 100 Kohm; 100lux: 5kohm
    // results(V) would be @100lux: 0,0315789474V; @10lux: 0,1224489796 to 0,5263157895V; @dark: 2,9311187103V.
    // ADC10MEM @100lux: 10.8; @10lux: 41.8 to 179.6; @dark: 1000.5
    // Using:
    // IF (ADC10MEM > 105) adc_lux = 0
    // Else adc_lux = -ADC10MEM + 111
    //if (ADC10MEM > 105) {
    //  adc_lux = 0;
    //} else {
    //  adc_lux = -ADC10MEM + 111; // -ADC10MEM + 111
    //}
    // Make calculations on the receiving device
    adc_lux = ADC10MEM;
    ADC10CTL0 &= ~(ADC10IE & ENC); // Disable conversion
    ADC10CTL0 = 0; // Disable ADC, some values must be cleared after ENC
    clock_getTime(&adc_luxTime);
    adc_flags |= ADC_FLAGLUXDONE;
    break;
  default:
    break;
  }
}