X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=heater.git;a=blobdiff_plain;f=firmware%2Fmain.c;h=76bed47f45f1f70895f4abc25bf1f9588ac8b988;hp=ddbd2d3cf54471fd8edf97dc0dbc87ae670f3dca;hb=d3b9a34d6b153bd04e7d233c2e2bbcecc70a6fa5;hpb=c1afb05fed7d9c526b606af5ff7e7883a2645038 diff --git a/firmware/main.c b/firmware/main.c index ddbd2d3..76bed47 100644 --- a/firmware/main.c +++ b/firmware/main.c @@ -27,16 +27,16 @@ * When running, the "-" button is used for decreasing the output power, * the "+" button is for increasing it. * When on the lowest power state, the "-" button switches the system off. - * TODO: Long "-" button press switches the system off, long "+" button + * Long "-" button press switches the system off, long "+" button * press sets the output power to maximum. * * Status LED: * When powering up by a button press, the LED goes on to provide a visual * feedback, and is switched off after the button is released. - * TODO: After a button press, the # of blinks of the LED reflects the + * After a button press, the # of blinks of the LED reflects the * chosen output power level for some time. Afterwards, it displays * the battery level. - * TODO: When the battery is completely exhausted, the output power is switched + * When the battery is completely exhausted, the output power is switched * off, the LED keeps blinking for some time, and then the whole system is * switched off to avoid deep discharge of the battery. * @@ -59,18 +59,66 @@ #define WAKEUP_POLL 50 // msec #define WAKEUP_LIMIT 5 // times WAKEUP_POLL -/* output power levels */ -#define N_STEPS 5 -static unsigned char steps[] = { 60, 85, 121, 171, 242 }; -static unsigned char intensity = 0; // selected power level - /* which state (output on or output off) are we measuring now */ static volatile unsigned char adc_type, adc_drop; +#define ADC_RUNAVG_SHIFT 5 // running average shift on batt_on, batt_off static volatile uint16_t batt_on, batt_off; // measured voltage +/* + * The voltage divider has 1M5 and 300K resistors (i.e. it measures 1/6th of + * the real voltage), ADC uses 1.1V internal reference. + * Macro to calculate upper eight bits of the ADC running-averaged value + * from the voltage in milivolts. + */ +#define ADC_1100MV_VALUE 1071 // measured, not exactly 1100 +#define MV_TO_ADC8(mV) ((unsigned char)(((uint32_t)(1UL << ADC_RUNAVG_SHIFT) \ + * (1024UL * (mV)) \ + / (6UL * ADC_1100MV_VALUE)) >> 8)) +static unsigned char batt_levels[] = { + MV_TO_ADC8(3350), + MV_TO_ADC8(3700), + MV_TO_ADC8(3900), +}; +#define BATT_N_LEVELS (sizeof(batt_levels) / sizeof(batt_levels[0])) + +/* output power and PWM calculation */ +#define PWM_TOP 255 +#define PWM_MAX (PWM_TOP - 8) // to allow for ADC "batt_off" measurements + +/* + * The values in power_levels[] array are voltages at which the load + * would give the expected power (we don't have sqrt() function, + * so we cannot use mW values directly. They can be calculated as + * voltage[V] = sqrt(load_resistance[Ohm] * expected_power[W]) + * or + * voltage[mV] = sqrt(load_resistance[mOhm] * expected_power[mW]) + * + * I use 1.25 W as minimum power, each step is sqrt(2)*previous_step, + * so the 5th step is 5 W. + */ +static unsigned char power_levels[] = { + MV_TO_ADC8(1581), // 1250 mW for 2 Ohm load + MV_TO_ADC8(1880), // 1768 mW for 2 Ohm load + MV_TO_ADC8(2236), // 2500 mW for 2 Ohm load + MV_TO_ADC8(2659), // 3536 mW for 2 Ohm load + MV_TO_ADC8(3162), // 5000 mW for 2 Ohm load +}; +#define N_POWER_LEVELS (sizeof(power_levels) / sizeof(power_levels[0])) + +static unsigned char power_level = 0; // selected power level +static unsigned char power_level_changed; // for visual feedback + +#define LED_PWRCHANGE_COUNT 3 +#define LED_BATTEMPTY_COUNT 60 + /* timing by WDT */ static volatile unsigned char jiffies, next_clock_tick; +/* button press duration (in jiffies) */ +#define BUTTON_SHORT_MIN 1 +#define BUTTON_LONG_MIN 10 + + /* ========= Analog to Digital Converter (battery voltage) ========== */ static void adc_init() { @@ -112,15 +160,15 @@ ISR(ADC_vect) // so don't bother with it. if (adc_type == 0) { if (batt_off) { - batt_off += adcw - (batt_off >> 5); + batt_off += adcw - (batt_off >> ADC_RUNAVG_SHIFT); } else { - batt_off = adcw << 5; + batt_off = adcw << ADC_RUNAVG_SHIFT; } } else { if (batt_on) { - batt_on += adcw - (batt_on >> 5); + batt_on += adcw - (batt_on >> ADC_RUNAVG_SHIFT); } else { - batt_on = adcw << 5; + batt_on = adcw << ADC_RUNAVG_SHIFT; } } } @@ -135,8 +183,9 @@ static void pwm_init() // TCCR1 = _BV(CS10); // clk/1 = 1 MHz TCCR1 = _BV(CS11) | _BV(CS13); // clk/512 = 2 kHz GTCCR = _BV(COM1B1) | _BV(PWM1B); - OCR1C = 255; - OCR1B = steps[0]; + OCR1C = PWM_TOP; + // OCR1B = steps[0]; + OCR1B = 0; TIMSK = _BV(OCIE1B) | _BV(TOIE1); } @@ -297,21 +346,97 @@ static void power_down() hw_setup(); } -/* ======== Button press detection and handling ===================== */ -static void button_one_pressed() +/* ============ Status LED blinking =================================== */ +static unsigned char blink_on_time, blink_off_time, n_blinks; +static unsigned char blink_counter; + +static unsigned char battery_level() +{ + unsigned char i, adc8; + + // NOTE: we use 8-bit value only, so we don't need lock to protect + // us against concurrently running ADC IRQ handler: + adc8 = batt_off >> 8; + + for (i = 0; i < BATT_N_LEVELS; i++) + if (batt_levels[i] > adc8) + break; + + return i; +} + +static void status_led_next_pattern() +{ + static unsigned char battery_exhausted; + + if (power_level_changed) { + power_level_changed--; + n_blinks = power_level + 1; + } else { + unsigned char b_level = battery_level(); + if (b_level) { + battery_exhausted = 0; + } else if (battery_exhausted) { + if (!--battery_exhausted) + power_down(); + } else { + battery_exhausted = LED_BATTEMPTY_COUNT; + } + + n_blinks = b_level + 1; + } + + blink_on_time = 2; + blink_off_time = 1; + blink_counter = 10; +} + +static void timer_blink() { - if (intensity > 0) { - pwm_set(steps[--intensity]); + if (blink_counter) { + blink_counter--; + } else if (!status_led_is_on()) { + status_led_on(); + blink_counter = blink_on_time; + } else if (n_blinks) { + --n_blinks; + status_led_off(); + blink_counter = blink_off_time; } else { - power_down(); + status_led_next_pattern(); } } -static void button_two_pressed() +/* ======== Button press detection and handling ===================== */ +static void button_pressed(unsigned char button, unsigned char long_press) { - if (intensity < N_STEPS-1) { - pwm_set(steps[++intensity]); + // ignore simlultaneous button 1 and 2 press + // Note: we set power_level_changed after each button press, + // even when the power is at maximum, to provide visual feedback + // with status LED. + if (long_press) { + if (button == 1) { + power_down(); + return; + } else if (button == 2) { + power_level = N_POWER_LEVELS-1; + } + } else { // short press + if (button == 1) { + if (power_level > 0) { + --power_level; + } else { + power_down(); + return; + } + } else if (button == 2) { + if (power_level < N_POWER_LEVELS-1) { + ++power_level; + } + } } + power_level_changed = LED_PWRCHANGE_COUNT; + status_led_next_pattern(); } static unsigned char button_state, button_state_time; @@ -321,8 +446,12 @@ static void timer_check_buttons() unsigned char newstate = buttons_pressed(); if (newstate == button_state) { - if (newstate && button_state_time < 4) + if (newstate && button_state_time < BUTTON_LONG_MIN) ++button_state_time; + + if (newstate && button_state_time >= BUTTON_LONG_MIN) { + status_led_on(); + } return; } @@ -333,51 +462,56 @@ static void timer_check_buttons() } // just released - switch (button_state) { - case 1: button_one_pressed(); - break; - case 2: button_two_pressed(); - break; - default: // ignore when both are preseed - break; - } + if (button_state_time >= BUTTON_SHORT_MIN) + button_pressed(button_state, + button_state_time >= BUTTON_LONG_MIN ? 1 : 0); button_state = newstate; + button_state_time = 0; } -/* ============ Status LED blinking =================================== */ -static unsigned char blink_on_time, blink_off_time, n_blinks; -static unsigned char blink_counter; - -static void status_led_next_pattern() +/* ===================== Output power control ======================== */ +static void calculate_power_level() { - // for now, display the selected intensity - n_blinks = intensity + 1; - blink_on_time = 0; - blink_off_time = 2; - blink_counter = 10; -} + uint32_t pwm; + unsigned char batt_on8; -static void timer_blink() -{ - if (blink_counter) { - blink_counter--; - } else if (status_led_is_on()) { - status_led_off(); - blink_counter = blink_off_time; - } else if (n_blinks) { - --n_blinks; - status_led_on(); - blink_counter = blink_on_time; - } else { - status_led_next_pattern(); + if (battery_level() == 0 || batt_on == 0) { + pwm_set(0); + // TODO power_down() after some time + return; } + + batt_on8 = batt_on >> 8; + + pwm = (uint32_t)PWM_TOP * power_levels[power_level] + * power_levels[power_level]; + pwm /= (uint32_t)batt_on8 * batt_on8; + + if (pwm > PWM_MAX) + pwm = PWM_MAX; + + log_byte(0x10 + power_level); + log_byte(batt_on8); + log_byte(pwm & 0xFF); + + pwm_set(pwm); } int main() { log_init(); +#if 0 + log_word(batt_levels[0]); + log_word(batt_levels[1]); + log_word(batt_levels[2]); + log_flush(); +#endif + log_byte(power_levels[0]); + log_byte(power_levels[4]); + log_flush(); + power_down(); sei(); @@ -395,8 +529,20 @@ int main() // FIXME: Maybe handle new ADC readings as well? if (next_clock_tick) { next_clock_tick = 0; - timer_check_buttons(); timer_blink(); + // this has to be after the timer_blink() call + // to override the status LED during long button press + timer_check_buttons(); + + if ((jiffies & 0x0F) == 0) { + calculate_power_level(); +#if 0 + log_byte(0xcc); + log_byte(i); + log_byte(batt_off >> 8); + log_byte(batt_on >> 8); +#endif + } log_flush(); } }