#include "lights.h"
-#define AMBIENT_ADC N_PWMLEDS
-#define BATTERY_ADC (N_PWMLEDS + 1)
-#define ADC1_GAIN20 (N_PWMLEDS + 2)
-#define BUTTON_ADC (N_PWMLEDS + 3)
-
-#define NUM_ADCS 7
-volatile static unsigned char current_adc;
-static uint16_t adc_sum;
-static unsigned char sum_shift;
-static unsigned char adc_vals;
+// pwmleds are measured continuously (when active)
+#define AMBIENT_ADC N_PWMLEDS // measured every jiffy (16 Hz)
+#define BUTTON_ADC (N_PWMLEDS + 1) // measured every jiffy (16 Hz)
+#define FIRST_16HZ_ADC BUTTON_ADC
+#define BATTERY_ADC (N_PWMLEDS + 2) // once per second
+#define ADC1_GAIN20 (N_PWMLEDS + 3) // once per second
+#define FIRST_1S_ADC ADC1_GAIN20
+#define ZERO_ADC (N_PWMLEDS + 4) // must be last
+
+#define NUM_ADCS ZERO_ADC
+
+struct {
+ unsigned char read_zero_log : 2;
+ unsigned char read_drop_log : 2;
+ unsigned char read_keep_log : 4;
+} adc_params[NUM_ADCS] = {
+ { 0, 1, PWMLED_ADC_SHIFT }, // pwmled 1
+ { 0, 1, PWMLED_ADC_SHIFT }, // pwmled 2
+ { 0, 1, PWMLED_ADC_SHIFT }, // pwmled 3
+ { 0, 1, AMBIENT_ADC_SHIFT }, // ambient
+ { 0, 1, 0 }, // buttons
+ { 0, 1, 0 }, // battery
+ { 0, 1, 0 }, // gain20
+};
+
+volatile unsigned char adc_is_on;
+
+volatile static unsigned char current_adc, slow_adcs_wanted;
+static uint16_t adc_sum, zero_count, drop_count, read_count, n_reads_log;
#define ADC1_GAIN20_OFFSET_SHIFT 6
static uint16_t adc1_gain20_offset;
-static void inline setup_mux(unsigned char n)
+
+static void setup_mux(unsigned char n)
{
- /* ADC numbering: PWM LEDs first, then ambient light sensor, battery sensor */
+ /* ADC numbering: PWM LEDs first, then others, zero at the end */
switch (n) {
case 0: // pwmled 1: 1.1V, ADC0,1 (PA0,1), gain 20
ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX1) | _BV(MUX0);
- sum_shift = PWMLED_ADC_SHIFT;
break;
case 1: // pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20
ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
- sum_shift = PWMLED_ADC_SHIFT;
break;
case 2: // pwmled 3: 1.1V, ADC4 (PA5), single-ended
ADMUX = _BV(REFS1) | _BV(MUX2);
- sum_shift = PWMLED_ADC_SHIFT;
break;
case AMBIENT_ADC: // ambient light: 1.1V, ADC5 (PA6), single-ended
ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
- sum_shift = 3; // 3 measurements
+ break;
+ case BUTTON_ADC: // buttons: 1.1V, ADC3, single-ended
+ PORTA |= _BV(PA3); // +5V to the voltage splitter
+ ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0);
break;
case BATTERY_ADC: // batt voltage: 1.1V, ADC6 (PA7), single-ended
ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX1);
- sum_shift = 0; // 1 measurement
break;
case ADC1_GAIN20: // gain stage offset: 1.1V, ADC1,1, gain 20
ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
- sum_shift = 0; // 1 measurement
break;
- case BUTTON_ADC: // buttons: 1.1V, ADC3, single-ended
- PORTA |= _BV(PA3); // +5V to the voltage splitter
- ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0);
- sum_shift = 0;
+ case ZERO_ADC: // zero: 1.1V, ADC1 (PA1), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX0);
break;
}
-
- adc_sum = 0;
- adc_vals = 1 << sum_shift;
}
static void start_next_adc()
{
- if (current_adc > 0)
+ if (slow_adcs_wanted) {
+ current_adc = slow_adcs_wanted;
+ slow_adcs_wanted = 0;
+ goto found;
+ }
+
+ if (current_adc > N_PWMLEDS) {
current_adc--;
+ goto found;
+ }
+
+ if (!TIMER1_IS_ON()) {
+ adc_is_on = 0;
+ return;
+ }
+
+ do {
+ if (!current_adc)
+ current_adc = N_PWMLEDS;
+ --current_adc;
+ } while (!PWM_IS_ON(current_adc));
+
+found:
+ adc_is_on = 1;
+
+ adc_sum = 0;
+ // we use the last iteration of zero_count to set up the MUX
+ // to its final destination, hence the "1 +" below:
+ if (adc_params[current_adc].read_zero_log)
+ zero_count = 1 + (1 << (adc_params[current_adc].read_zero_log-1));
else
- // TODO: kick the watchdog here.
- current_adc = NUM_ADCS-1;
+ zero_count = 1;
+
+ if (adc_params[current_adc].read_drop_log)
+ drop_count = 1 << (adc_params[current_adc].read_drop_log - 1);
+ else
+ drop_count = 0;
+
+ read_count = 1 << adc_params[current_adc].read_keep_log;
+ n_reads_log = adc_params[current_adc].read_keep_log;
// set up mux, start one-shot conversion
- setup_mux(current_adc);
+ if (zero_count > 1)
+ setup_mux(ZERO_ADC);
+ else
+ setup_mux(current_adc);
+
ADCSRA |= _BV(ADSC);
}
+void timer_start_slow_adcs()
+{
+ if ((jiffies & 0x000F) == 0) {
+ slow_adcs_wanted = FIRST_1S_ADC;
+ } else {
+ slow_adcs_wanted = FIRST_16HZ_ADC;
+ }
+
+ if (!adc_is_on) {
+ start_next_adc();
+ }
+}
+
/*
* Single synchronous ADC conversion.
* Has to be called with IRQs disabled (or with the ADC IRQ disabled).
void init_adc()
{
unsigned char i;
- current_adc = NUM_ADCS;
+ current_adc = 0;
+ adc_is_on = 1;
+ slow_adcs_wanted = FIRST_1S_ADC;
ADCSRA = _BV(ADEN) // enable
| _BV(ADPS1) | _BV(ADPS0) // CLK/8 = 125 kHz
DIDR0 = 0;
}
+static void adc1_gain20_adc(uint16_t adcsum)
+{
+ // running average
+ adc1_gain20_offset += adcsum
+ - (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
+}
+
ISR(ADC_vect) { // IRQ handler
uint16_t adcval = ADCW;
- if (adc_vals)
- // start the next conversion immediately
- ADCSRA |= _BV(ADSC);
+ /*
+ * After the timer interrupt, drop the current reading.
+ * We may have changed the PWM outputs, so the value is
+ * probably useless anyway.
+ * FIXME: possible race condition - we should make an explicit
+ * notification inside the timer IRQ handler.
+ */
+ if (slow_adcs_wanted) {
+ start_next_adc();
+ return;
+ }
- if (adc_vals < (1 << sum_shift))
- // drop the first conversion, use all others
- adc_sum += adcval;
+ if (zero_count) {
+ if (zero_count > 1) {
+ ADCSRA |= _BV(ADSC);
+ zero_count--;
+ return;
+ } else {
+ setup_mux(current_adc);
+ zero_count = 0;
+ /* fall through */
+ }
+ }
- if (adc_vals) {
- adc_vals--;
+ if (drop_count) {
+ ADCSRA |= _BV(ADSC); // drop this one, start the next
+ drop_count--;
return;
}
- // Now handle the (1 << sum_shift) measurements
+ if (read_count) {
+ ADCSRA |= _BV(ADSC);
+ adc_sum += adcval;
+ read_count--;
+ pwm_timer();
+ return;
+ }
- adcval = adc_sum >> sum_shift;
+ /*
+ * Now we have performed read_count measurements and have them
+ * in adc_sum.
+ */
- if (current_adc == ADC1_GAIN20) {
- // running average
- adc1_gain20_offset += adcval
- - (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
- } else if (current_adc == 0 || current_adc == 1) {
+ // For inputs with gain, subtract the measured gain stage offset
+ if (current_adc < 2) {
uint16_t offset = adc1_gain20_offset
- >> (ADC1_GAIN20_OFFSET_SHIFT - sum_shift);
+ >> (ADC1_GAIN20_OFFSET_SHIFT - n_reads_log);
+
if (adc_sum > offset)
adc_sum -= offset;
else
adc_sum = 0;
}
- if (current_adc < N_PWMLEDS)
+ switch (current_adc) {
+ case 0:
+ case 1:
+ case 2:
pwmled_adc(current_adc, adc_sum);
- if (current_adc == AMBIENT_ADC)
+ break;
+ case AMBIENT_ADC:
ambient_adc(adc_sum);
- if (current_adc == BATTERY_ADC)
- battery_adc(adcval);
- if (current_adc == BUTTON_ADC)
- button_adc(adcval);
-
+ break;
+ case BUTTON_ADC:
+ button_adc(adc_sum);
+ break;
+ case BATTERY_ADC:
+ battery_adc(adc_sum);
+ break;
+ case ADC1_GAIN20:
+ adc1_gain20_adc(adcval);
+ break;
+ }
+
start_next_adc();
}
https://www.fi.muni.cz/~kas/git / bike-lights.git / blobdiff