#include "lights.h"
-/* ADC numbering: PWM LEDs first, then ambient light sensor, battery sensor */
-static unsigned char adc_mux[] = { // pwmleds should be first
- // 0: pwmled 0: 1.1V, ADC3 (PA4), single-ended
- _BV(REFS1) | _BV(MUX1) | _BV(MUX0),
- // 1: pwmled 1: 1.1V, ADC0,1 (PA0,1), gain 1 or 8
- _BV(REFS1) | _BV(MUX3) | _BV(MUX2),
- // 2: pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20 or 32
- _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1),
- // 3: ambient light: 1.1V, ADC4 (PA5), single-ended
- _BV(REFS1) | _BV(MUX2),
- // 4: batt voltage: 1.1V, ADC5 (PA6), single-ended
- _BV(REFS1) | _BV(MUX2) | _BV(MUX0),
-};
-
#define AMBIENT_ADC N_PWMLEDS
#define BATTERY_ADC (N_PWMLEDS + 1)
+#define ADC1_GAIN20 (N_PWMLEDS + 2)
+#define BUTTON_ADC (N_PWMLEDS + 2)
-#define LAST_ADC (sizeof(adc_mux)/sizeof(adc_mux[0]))
+#define NUM_ADCS 7
volatile static unsigned char current_adc;
-static unsigned char adc_ignore;
+static uint16_t adc_sum;
+static unsigned char sum_shift;
+static unsigned char adc_vals;
+#define ADC1_GAIN20_OFFSET_SHIFT 6
+static uint16_t adc1_gain20_offset;
-static void start_next_adc()
+static void inline setup_mux(unsigned char n)
{
- while (current_adc > 0) {
- --current_adc;
-
- // test if current_adc should be measured
- if (current_adc < N_PWMLEDS && pwmled_needs_adc(current_adc))
- goto found;
- if (current_adc == AMBIENT_ADC)
- goto found;
- // TODO battery sense, etc.
+ /* ADC numbering: PWM LEDs first, then ambient light sensor, battery sensor */
+ 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 3: // ambient light: 1.1V, ADC5 (PA6), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
+ sum_shift = 3; // 3 measurements
+ break;
+ case 4: // batt voltage: 1.1V, ADC6 (PA7), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX1);
+ sum_shift = 0; // 1 measurement
+ break;
+ case 5: // 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 6: // buttons: 1.1V, ADC3, single-ended
+ PORTA |= _BV(PA3); // +5V to the voltage splitter
+ ADMUX = _BV(REFS1) | _BV(MUX1) | _BV(MUX0);
+ sum_shift = 0;
+ break;
}
- // all ADCs have been handled
- current_adc = LAST_ADC;
- return;
-found:
- // ADCSRB |= _BV(GSEL); // gain 8 or 32
- ADMUX = adc_mux[current_adc]; // set up mux, start one-shot conversion
- adc_ignore = 1; // ignore first reading after mux change
+ adc_sum = 0;
+ adc_vals = 1 << sum_shift;
+}
+
+static void start_next_adc()
+{
+ if (current_adc > 0)
+ current_adc--;
+ else
+ // TODO: kick the watchdog here.
+ current_adc = NUM_ADCS-1;
+
+ // set up mux, start one-shot conversion
+ setup_mux(current_adc);
ADCSRA |= _BV(ADSC);
}
+/*
+ * Single synchronous ADC conversion.
+ * Has to be called with IRQs disabled (or with the ADC IRQ disabled).
+ */
+static uint16_t read_adc_sync()
+{
+ uint16_t rv;
+
+ ADCSRA |= _BV(ADSC); // start the conversion
+
+ // wait for the conversion to finish
+ while((ADCSRA & _BV(ADIF)) == 0)
+ ;
+
+ rv = ADCW;
+ ADCSRA |= _BV(ADIF); // clear the IRQ flag
+
+ return rv;
+}
+
void init_adc()
{
- current_adc = LAST_ADC;
- adc_ignore = 1;
+ unsigned char i;
+ current_adc = NUM_ADCS;
ADCSRA = _BV(ADEN) // enable
| _BV(ADPS1) | _BV(ADPS0) // CLK/8 = 125 kHz
// | _BV(ADPS2) // CLK/16 = 62.5 kHz
;
- ADCSRB |= _BV(GSEL); // gain 8 or 32
+ // ADCSRB |= _BV(GSEL); // gain 8 or 32
// Disable digital input on all bits used by ADC
DIDR0 = _BV(ADC0D) | _BV(ADC1D) | _BV(ADC2D) | _BV(ADC3D)
- | _BV(ADC4D) | _BV(ADC5D);
+ | _BV(ADC4D) | _BV(ADC5D) | _BV(ADC6D);
- ADCSRA |= _BV(ADSC);
+ // 1.1V, ADC1,1, gain 20
+ ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
/* Do first conversion and drop the result */
- while ((ADCSRA & _BV(ADIF)) == 0)
- ;
- ADCSRA |= _BV(ADIF); // clear the IRQ flag
+ read_adc_sync();
+
+ adc1_gain20_offset = 0;
+
+ for (i = 0; i < (1 << ADC1_GAIN20_OFFSET_SHIFT); i++) {
+ adc1_gain20_offset += read_adc_sync()
+ - (adc1_gain20_offset >> ADC1_GAIN20_OFFSET_SHIFT);
+ }
ADCSRA |= _BV(ADIE); // enable IRQ
+
+ start_next_adc();
+}
+
+void susp_adc()
+{
+ ADCSRA = 0;
+ DIDR0 = 0;
}
ISR(ADC_vect) { // IRQ handler
uint16_t adcval = ADCW;
-#if 0
- log_byte(0xF3);
- log_byte(current_adc);
- log_word(adcval);
-#endif
-
- if (adc_ignore) {
+ if (adc_vals)
+ // start the next conversion immediately
ADCSRA |= _BV(ADSC);
- adc_ignore = 0;
+
+ if (adc_vals < (1 << sum_shift))
+ // drop the first conversion, use all others
+ adc_sum += adcval;
+
+ if (adc_vals) {
+ adc_vals--;
return;
}
+ // Now handle the (1 << sum_shift) measurements
+
+ adcval = adc_sum >> sum_shift;
+
+ 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) {
+ uint16_t offset = adc1_gain20_offset
+ >> (ADC1_GAIN20_OFFSET_SHIFT - sum_shift);
+ if (adc_sum > offset)
+ adc_sum -= offset;
+ else
+ adc_sum = 0;
+ }
+
if (current_adc < N_PWMLEDS)
- pwmled_adc(current_adc, adcval);
+ pwmled_adc(current_adc, adc_sum);
if (current_adc == AMBIENT_ADC)
- ambient_adc(adcval);
- // TODO battery sense, etc.
+ ambient_adc(adc_sum);
+ if (current_adc == BATTERY_ADC)
+ battery_adc(adcval);
+ if (current_adc == BUTTON_ADC)
+ button_adc(adcval);
start_next_adc();
}
-void timer_start_adcs()
-{
- if (current_adc == LAST_ADC) // Don't start if in progress
- start_next_adc();
-}
-
https://www.fi.muni.cz/~kas/git / bike-lights.git / blobdiff