* 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.
*
#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;
#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;
#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
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)
batt_on = adcw << ADC_RUNAVG_SHIFT;
}
}
+ ADCSRA &= ~_BV(ADIE);
}
/* ===================== Timer/Counter1 for PWM ===================== */
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);
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)
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)
);
}
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)
{
if (long_press) {
if (button == 1) {
power_down();
+ return;
} else if (button == 2) {
power_level = N_POWER_LEVELS-1;
}
--power_level;
} else {
power_down();
+ return;
}
} else if (button == 2) {
if (power_level < N_POWER_LEVELS-1) {
}
}
}
+ status_led_next_pattern();
}
static unsigned char button_state, button_state_time;
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()
log_word(batt_levels[2]);
log_flush();
#endif
+ log_byte(power_levels[0]);
+ log_byte(power_levels[4]);
+ log_flush();
power_down();
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);
https://www.fi.muni.cz/~kas/git / heater.git / blobdiff