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=0d45ac93d9a6429bc040486f173f93a2f7d9b0bc;hp=5c9a566ffc0ea20afb54abefc0330cd0795f2a7e;hb=e847a9fc0c504419a8e2f93a813312d0be94c7ef;hpb=0202c0c1fd50a0817b7a83f55b0a2615d706c91f diff --git a/firmware/main.c b/firmware/main.c index 5c9a566..0d45ac9 100644 --- a/firmware/main.c +++ b/firmware/main.c @@ -33,10 +33,9 @@ * 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 - * 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 + * It displays the current power level and current battery voltage + * using # of blinks with different blinking lengths. + * 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. * @@ -59,13 +58,15 @@ #define WAKEUP_POLL 50 // msec #define WAKEUP_LIMIT 5 // times WAKEUP_POLL -/* output power levels */ -#define N_POWER_LEVELS 5 -static unsigned char power_levels[N_POWER_LEVELS] = { +// #define BUTTONS_REVERSE -}; - -static unsigned char power_level = 0; // selected power level +#ifdef BUTTONS_REVERSE +# define BUTTON1 PB0 +# define BUTTON2 PB1 +#else +# define BUTTON1 PB1 +# define BUTTON2 PB0 +#endif /* !BUTTONS_REVERSE */ /* which state (output on or output off) are we measuring now */ static volatile unsigned char adc_type, adc_drop; @@ -82,12 +83,41 @@ static volatile uint16_t batt_on, batt_off; // measured voltage #define MV_TO_ADC8(mV) ((unsigned char)(((uint32_t)(1UL << ADC_RUNAVG_SHIFT) \ * (1024UL * (mV)) \ / (6UL * ADC_1100MV_VALUE)) >> 8)) -#define BATT_N_LEVELS 3 -static unsigned char batt_levels[BATT_N_LEVELS] = { - MV_TO_ADC8(3500), +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 +#define PWM_MIN 8 // to allow for ADC "batt_on" 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 + +#define LED_BATTEMPTY_COUNT 60 /* timing by WDT */ static volatile unsigned char jiffies, next_clock_tick; @@ -96,14 +126,14 @@ static volatile unsigned char jiffies, next_clock_tick; #define BUTTON_SHORT_MIN 1 #define BUTTON_LONG_MIN 10 + /* ========= Analog to Digital Converter (battery voltage) ========== */ static void adc_init() { power_adc_enable(); - ADCSRA = _BV(ADEN) // enable - | _BV(ADPS1) | _BV(ADPS0) // clk/8 = 125 kHz - | _BV(ADIE); // enable IRQ + ADCSRA = _BV(ADEN) // enable + | _BV(ADPS1) | _BV(ADPS0); // clk/8 = 125 kHz ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0); // 1.1V reference, PB3 pin, single-ended DIDR0 |= _BV(ADC3D); // PB3 pin as analog input @@ -111,15 +141,17 @@ static void adc_init() static void adc_susp() { - ADCSRA &= ~_BV(ADEN); // disable ADC + ADCSRA = 0; // disable ADC DIDR0 &= ~_BV(ADC3D); // disable analog input on PB3 power_adc_disable(); } -static void adc_start_measurement() +static void adc_start_measurement(unsigned char on) { - ADCSRA |= _BV(ADSC); + adc_drop = 1; + adc_type = on; + ADCSRA |= _BV(ADSC) | _BV(ADIE); } ISR(ADC_vect) @@ -148,6 +180,7 @@ ISR(ADC_vect) batt_on = adcw << ADC_RUNAVG_SHIFT; } } + ADCSRA &= ~_BV(ADIE); } /* ===================== Timer/Counter1 for PWM ===================== */ @@ -156,11 +189,20 @@ static void pwm_init() power_timer1_enable(); DDRB |= _BV(PB4); + PORTB &= ~_BV(PB4); // TCCR1 = _BV(CS10); // clk/1 = 1 MHz - TCCR1 = _BV(CS11) | _BV(CS13); // clk/512 = 2 kHz + // TCCR1 = _BV(CS11) | _BV(CS13); // clk/512 = 2 kHz + /* + * clk/64 = 16 kHz. We use PWM_MIN and PWM_MAX, so we have at least + * 8 full T/C1 cycles to do two ADC measurements. The ADC with 125 kHz + * clock can do about 7000-9000 measurement per second, so we should + * be safe both on low and high OCR1B values with this clock + */ + TCCR1 = _BV(CS12) | _BV(CS11) | _BV(CS10); + GTCCR = _BV(COM1B1) | _BV(PWM1B); - OCR1C = 255; + OCR1C = PWM_TOP; // OCR1B = steps[0]; OCR1B = 0; TIMSK = _BV(OCIE1B) | _BV(TOIE1); @@ -169,20 +211,19 @@ static void pwm_init() static void pwm_susp() { TCCR1 = 0; + TIMSK = 0; + GTCCR = 0; + PORTB &= ~_BV(PB4); } ISR(TIM1_OVF_vect) { - adc_drop = 2; - adc_type = 1; - adc_start_measurement(); + adc_start_measurement(1); } ISR(TIM1_COMPB_vect) { - adc_drop = 2; - adc_type = 0; - adc_start_measurement(); + adc_start_measurement(0); } static void pwm_set(unsigned char pwm) @@ -233,9 +274,9 @@ static void buttons_susp() static unsigned char buttons_pressed() { return ( - (PINB & _BV(PB0) ? 0 : 1) + (PINB & _BV(BUTTON1) ? 0 : 1) | - (PINB & _BV(PB1) ? 0 : 2) + (PINB & _BV(BUTTON2) ? 0 : 2) ); } @@ -323,6 +364,70 @@ static void power_down() hw_setup(); } +/* ============ 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; + static unsigned char display_power_level; + + if (display_power_level) { + n_blinks = power_level + 1; + blink_on_time = 1; + blink_off_time = 2; + } 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 = 3; + blink_off_time = 0; + } + + blink_counter = 10; + display_power_level = !display_power_level; +} + +static void timer_blink() +{ + 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 { + status_led_next_pattern(); + } +} + /* ======== Button press detection and handling ===================== */ static void button_pressed(unsigned char button, unsigned char long_press) { @@ -330,6 +435,7 @@ static void button_pressed(unsigned char button, unsigned char long_press) if (long_press) { if (button == 1) { power_down(); + return; } else if (button == 2) { power_level = N_POWER_LEVELS-1; } @@ -339,6 +445,7 @@ static void button_pressed(unsigned char button, unsigned char long_press) --power_level; } else { power_down(); + return; } } else if (button == 2) { if (power_level < N_POWER_LEVELS-1) { @@ -346,6 +453,7 @@ static void button_pressed(unsigned char button, unsigned char long_press) } } } + status_led_next_pattern(); } static unsigned char button_state, button_state_time; @@ -379,50 +487,41 @@ static void timer_check_buttons() button_state_time = 0; } -/* ============ Status LED blinking =================================== */ -static unsigned char blink_on_time, blink_off_time, n_blinks; -static unsigned char blink_counter; - -static unsigned char battery_level() +/* ===================== Output power control ======================== */ +static void calculate_power_level() { - unsigned char i, adc8; + uint32_t pwm; + unsigned char batt_on8; - // 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; + if (battery_level() == 0) { + pwm_set(0); + // TODO power_down() after some time + return; + } - for (i = 0; i < BATT_N_LEVELS; i++) - if (batt_levels[i] > adc8) - break; + if (!batt_on) { + batt_on = batt_off; + }; - return i; -} + batt_on8 = batt_on >> 8; -static void status_led_next_pattern() -{ + pwm = (uint32_t)PWM_TOP * power_levels[power_level] + * power_levels[power_level]; + pwm /= (uint32_t)batt_on8 * batt_on8; - // for now, display the selected intensity - n_blinks = power_level + 1; - // n_blinks = battery_level() + 1; - blink_on_time = 0; - blink_off_time = 2; - blink_counter = 10; -} + if (pwm > PWM_MAX) + pwm = PWM_MAX; -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 (pwm < PWM_MIN) + pwm = PWM_MIN; + +#if 0 + log_byte(0x10 + power_level); + log_byte(batt_on8); + log_byte(pwm & 0xFF); +#endif + + pwm_set(pwm); } int main() @@ -435,6 +534,9 @@ int main() log_word(batt_levels[2]); log_flush(); #endif + log_byte(power_levels[0]); + log_byte(power_levels[4]); + log_flush(); power_down(); @@ -459,12 +561,7 @@ int main() timer_check_buttons(); if ((jiffies & 0x0F) == 0) { - unsigned char i; - - for (i = 0; i < BATT_N_LEVELS; i++) - if (batt_levels[i] > batt_off) - break; - + calculate_power_level(); #if 0 log_byte(0xcc); log_byte(i);