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+/*
+ * fsm-adc.c: ADC (voltage, temperature) functions for SpaghettiMonster.
+ *
+ * Copyright (C) 2017 Selene ToyKeeper
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef FSM_ADC_C
+#define FSM_ADC_C
+
+#ifdef USE_VOLTAGE_DIVIDER
+// 1.1V / pin7
+#define ADMUX_VOLTAGE ADMUX_VOLTAGE_DIVIDER
+#else
+// VCC / 1.1V reference
+#define ADMUX_VOLTAGE ADMUX_VCC
+#endif
+
+inline void ADC_on()
+{
+ // read voltage on VCC by default
+ ADMUX = ADMUX_VOLTAGE;
+ #ifdef USE_VOLTAGE_DIVIDER
+ // disable digital input on divider pin to reduce power consumption
+ DIDR0 |= (1 << VOLTAGE_ADC_DIDR);
+ #else
+ // disable digital input on VCC pin to reduce power consumption
+ //DIDR0 |= (1 << ADC_DIDR); // FIXME: unsure how to handle for VCC pin
+ #endif
+ // enable, start, prescale
+ ADCSRA = (1 << ADEN) | (1 << ADSC) | ADC_PRSCL;
+}
+
+inline void ADC_off() {
+ ADCSRA &= ~(1<<ADEN); //ADC off
+}
+
+#ifdef USE_VOLTAGE_DIVIDER
+static inline uint8_t calc_voltage_divider(uint16_t value) {
+ // use 9.7 fixed-point to get sufficient precision
+ uint16_t adc_per_volt = ((ADC_44<<7) - (ADC_22<<7)) / (44-22);
+ // incoming value is 14.2 fixed-point, so shift it 2 bits less
+ uint8_t result = ((value<<5) / adc_per_volt) + VOLTAGE_FUDGE_FACTOR;
+ return result;
+}
+#endif
+
+// Each full cycle runs 7.8X per second with just voltage enabled,
+// or 3.9X per second with voltage and temperature.
+#if defined(USE_LVP) && defined(USE_THERMAL_REGULATION)
+#define ADC_CYCLES_PER_SECOND 4
+#else
+#define ADC_CYCLES_PER_SECOND 8
+#endif
+// TODO: is this better done in main() or WDT()?
+ISR(ADC_vect) {
+ // For some reason, the ADC interrupt is getting called a *lot*
+ // more often than it should be, like it's auto-triggering after each
+ // measurement, but I don't know why, or how to turn that off...
+ // So, skip every call except when explicitly requested.
+ if (! adcint_enable) return;
+ adcint_enable = 0;
+
+ static uint8_t adc_step = 0;
+
+ // LVP declarations
+ #ifdef USE_LVP
+ #ifdef USE_LVP_AVG
+ #define NUM_VOLTAGE_VALUES 4
+ static int16_t voltage_values[NUM_VOLTAGE_VALUES];
+ #endif
+ static uint8_t lvp_timer = 0;
+ static uint8_t lvp_lowpass = 0;
+ #define LVP_TIMER_START (VOLTAGE_WARNING_SECONDS*ADC_CYCLES_PER_SECOND) // N seconds between LVP warnings
+ #define LVP_LOWPASS_STRENGTH ADC_CYCLES_PER_SECOND // lowpass for one second
+ #endif
+
+ // thermal declarations
+ #ifdef USE_THERMAL_REGULATION
+ #define NUM_THERMAL_VALUES 8
+ #define NUM_THERMAL_VALUES_HISTORY 16
+ #define NUM_THERMAL_PROJECTED_HISTORY 8
+ #define ADC_STEPS 4
+ static int16_t temperature_values[NUM_THERMAL_VALUES]; // last few readings in C
+ static int16_t temperature_history[NUM_THERMAL_VALUES_HISTORY]; // 14.1 fixed-point
+ static int16_t projected_temperature_history[NUM_THERMAL_PROJECTED_HISTORY]; // 14.1 fixed-point
+ static uint8_t projected_temperature_history_counter = 0;
+ static uint8_t temperature_timer = 0;
+ static uint8_t overheat_lowpass = 0;
+ static uint8_t underheat_lowpass = 0;
+ #define TEMPERATURE_TIMER_START (THERMAL_WARNING_SECONDS*ADC_CYCLES_PER_SECOND) // N seconds between thermal regulation events
+ #define OVERHEAT_LOWPASS_STRENGTH ADC_CYCLES_PER_SECOND // lowpass for one second
+ #define UNDERHEAT_LOWPASS_STRENGTH ADC_CYCLES_PER_SECOND // lowpass for one second
+ #else
+ #define ADC_STEPS 2
+ #endif
+
+ uint16_t measurement = ADC; // latest 10-bit ADC reading
+
+ adc_step = (adc_step + 1) & (ADC_STEPS-1);
+
+ #ifdef USE_LVP
+ // voltage
+ if (adc_step == 1) {
+ #ifdef USE_LVP_AVG
+ // prime on first execution
+ if (voltage == 0) {
+ for(uint8_t i=0; i<NUM_VOLTAGE_VALUES; i++)
+ voltage_values[i] = measurement;
+ voltage = 42; // Life, the Universe, and Everything (*)
+ } else {
+ uint16_t total = 0;
+ uint8_t i;
+ for(i=0; i<NUM_VOLTAGE_VALUES-1; i++) {
+ voltage_values[i] = voltage_values[i+1];
+ total += voltage_values[i];
+ }
+ voltage_values[i] = measurement;
+ total += measurement;
+ total = total >> 2;
+
+ #ifdef USE_VOLTAGE_DIVIDER
+ voltage = calc_voltage_divider(total);
+ #else
+ voltage = (uint16_t)(1.1*1024*10)/total + VOLTAGE_FUDGE_FACTOR;
+ #endif
+ }
+ #else // no USE_LVP_AVG
+ #ifdef USE_VOLTAGE_DIVIDER
+ voltage = calc_voltage_divider(measurement);
+ #else
+ // calculate actual voltage: volts * 10
+ // ADC = 1.1 * 1024 / volts
+ // volts = 1.1 * 1024 / ADC
+ //voltage = (uint16_t)(1.1*1024*10)/measurement + VOLTAGE_FUDGE_FACTOR;
+ voltage = ((uint16_t)(2*1.1*1024*10)/measurement + VOLTAGE_FUDGE_FACTOR) >> 1;
+ #endif
+ #endif
+ // if low, callback EV_voltage_low / EV_voltage_critical
+ // (but only if it has been more than N ticks since last call)
+ if (lvp_timer) {
+ lvp_timer --;
+ } else { // it has been long enough since the last warning
+ if (voltage < VOLTAGE_LOW) {
+ if (lvp_lowpass < LVP_LOWPASS_STRENGTH) {
+ lvp_lowpass ++;
+ } else {
+ // try to send out a warning
+ //uint8_t err = emit(EV_voltage_low, 0);
+ //uint8_t err = emit_now(EV_voltage_low, 0);
+ emit(EV_voltage_low, 0);
+ //if (!err) {
+ // on successful warning, reset counters
+ lvp_timer = LVP_TIMER_START;
+ lvp_lowpass = 0;
+ //}
+ }
+ } else {
+ // voltage not low? reset count
+ lvp_lowpass = 0;
+ }
+ }
+ }
+ #endif // ifdef USE_LVP
+
+
+ #ifdef USE_THERMAL_REGULATION
+ // temperature
+ else if (adc_step == 3) {
+ // Convert ADC units to Celsius (ish)
+ int16_t temp = measurement - 275 + THERM_CAL_OFFSET + therm_cal_offset;
+
+ // prime on first execution
+ if (reset_thermal_history) {
+ reset_thermal_history = 0;
+ for(uint8_t i=0; i<NUM_THERMAL_VALUES; i++)
+ temperature_values[i] = temp;
+ for(uint8_t i=0; i<NUM_THERMAL_VALUES_HISTORY; i++)
+ temperature_history[i] = temp<<1;
+ for(uint8_t i=0; i<NUM_THERMAL_PROJECTED_HISTORY; i++)
+ projected_temperature_history[i] = temp<<1;
+ temperature = temp<<1;
+ } else { // update our current temperature estimate
+ uint8_t i;
+ int16_t total=0;
+
+ // rotate array
+ // FIXME: just move the index, don't move the values?
+ for(i=0; i<NUM_THERMAL_VALUES-1; i++) {
+ temperature_values[i] = temperature_values[i+1];
+ total += temperature_values[i];
+ }
+ temperature_values[i] = temp;
+ total += temp;
+
+ // Divide back to original range:
+ //temperature = total >> 2;
+ // More precise method: use noise as extra precision
+ // (values are now basically fixed-point, signed 13.2)
+ //temperature = total;
+ // 14.1 is less prone to overflows
+ temperature = total >> 2;
+ }
+
+ // guess what the temperature will be in a few seconds
+ int16_t pt;
+ {
+ uint8_t i;
+ int16_t diff;
+ int16_t t = temperature;
+
+ // algorithm tweaking; not really intended to be modified
+ // how far ahead should we predict?
+ #define THERM_PREDICTION_STRENGTH 4
+ // how proportional should the adjustments be?
+ #define THERM_DIFF_ATTENUATION 3
+ // acceptable temperature window size in C
+ #define THERM_WINDOW_SIZE 10
+ // highest temperature allowed
+ // (convert configured value to 14.1 fixed-point)
+ #define THERM_CEIL (((int16_t)therm_ceil)<<1)
+ // bottom of target temperature window (14.1 fixed-point)
+ #define THERM_FLOOR (THERM_CEIL - (THERM_WINDOW_SIZE<<1))
+
+ // rotate measurements and add a new one
+ for (i=0; i<NUM_THERMAL_VALUES_HISTORY-1; i++) {
+ temperature_history[i] = temperature_history[i+1];
+ }
+ temperature_history[NUM_THERMAL_VALUES_HISTORY-1] = t;
+
+ // guess what the temp will be several seconds in the future
+ // diff = rate of temperature change
+ //diff = temperature_history[NUM_THERMAL_VALUES_HISTORY-1] - temperature_history[0];
+ diff = t - temperature_history[0];
+ // projected_temperature = current temp extended forward by amplified rate of change
+ //projected_temperature = temperature_history[NUM_THERMAL_VALUES_HISTORY-1] + (diff<<THERM_PREDICTION_STRENGTH);
+ pt = projected_temperature = t + (diff<<THERM_PREDICTION_STRENGTH);
+
+ // store prediction for later averaging
+ projected_temperature_history[projected_temperature_history_counter] = pt;
+ projected_temperature_history_counter = (projected_temperature_history_counter + 1) & (NUM_THERMAL_PROJECTED_HISTORY-1);
+ }
+
+ // average prediction to reduce noise
+ int16_t avg_projected_temperature = 0;
+ uint8_t i;
+ for (i = 0;
+ (i < NUM_THERMAL_PROJECTED_HISTORY) && (avg_projected_temperature < 16000);
+ i++)
+ avg_projected_temperature += projected_temperature_history[i];
+ avg_projected_temperature /= NUM_THERMAL_PROJECTED_HISTORY;
+ //avg_projected_temperature /= i;
+
+ // cancel counters if appropriate
+ if (pt > THERM_FLOOR) {
+ underheat_lowpass = 0; // we're probably not too cold
+ } else if (pt < THERM_CEIL) {
+ overheat_lowpass = 0; // we're probably not too hot
+ }
+
+ if (temperature_timer) {
+ temperature_timer --;
+ } else { // it has been long enough since the last warning
+
+ // Too hot?
+ if (avg_projected_temperature > THERM_CEIL) {
+ if (overheat_lowpass < OVERHEAT_LOWPASS_STRENGTH) {
+ overheat_lowpass ++;
+ } else {
+ // reset counters
+ overheat_lowpass = 0;
+ temperature_timer = TEMPERATURE_TIMER_START;
+ // how far above the ceiling?
+ int16_t howmuch = (avg_projected_temperature - THERM_CEIL) >> THERM_DIFF_ATTENUATION;
+ if (howmuch > 0) {
+ // try to send out a warning
+ emit(EV_temperature_high, howmuch);
+ }
+ }
+ }
+
+ // Too cold?
+ else if (avg_projected_temperature < THERM_FLOOR) {
+ if (underheat_lowpass < UNDERHEAT_LOWPASS_STRENGTH) {
+ underheat_lowpass ++;
+ } else {
+ // reset counters
+ underheat_lowpass = 0;
+ temperature_timer = TEMPERATURE_TIMER_START;
+ // how far below the floor?
+ int16_t howmuch = (THERM_FLOOR - avg_projected_temperature) >> THERM_DIFF_ATTENUATION;
+ if (howmuch > 0) {
+ // try to send out a warning (unless voltage is low)
+ // (LVP and underheat warnings fight each other)
+ if (voltage > VOLTAGE_LOW)
+ emit(EV_temperature_low, howmuch);
+ }
+ }
+ }
+ }
+ }
+ #endif // ifdef USE_THERMAL_REGULATION
+
+
+ // set the correct type of measurement for next time
+ #ifdef USE_THERMAL_REGULATION
+ #ifdef USE_LVP
+ if (adc_step < 2) ADMUX = ADMUX_VOLTAGE;
+ else ADMUX = ADMUX_THERM;
+ #else
+ ADMUX = ADMUX_THERM;
+ #endif
+ #else
+ #ifdef USE_LVP
+ ADMUX = ADMUX_VOLTAGE;
+ #endif
+ #endif
+}
+
+#ifdef USE_BATTCHECK
+#ifdef BATTCHECK_4bars
+PROGMEM const uint8_t voltage_blinks[] = {
+ 30, 35, 38, 40, 42, 99,
+};
+#endif
+#ifdef BATTCHECK_6bars
+PROGMEM const uint8_t voltage_blinks[] = {
+ 30, 34, 36, 38, 40, 41, 43, 99,
+};
+#endif
+#ifdef BATTCHECK_8bars
+PROGMEM const uint8_t voltage_blinks[] = {
+ 30, 33, 35, 37, 38, 39, 40, 41, 42, 99,
+};
+#endif
+void battcheck() {
+ #ifdef BATTCHECK_VpT
+ blink_num(voltage);
+ #else
+ uint8_t i;
+ for(i=0;
+ voltage >= pgm_read_byte(voltage_blinks + i);
+ i++) {}
+ #ifdef DONT_DELAY_AFTER_BATTCHECK
+ blink_digit(i);
+ #else
+ if (blink_digit(i))
+ nice_delay_ms(1000);
+ #endif
+ #endif
+}
+#endif
+
+#endif
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