#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 + 3)
+#define ZERO_ADC (N_PWMLEDS + 4)
+
+#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 }, // battery
+ { 0, 1, 0 }, // gain20
+ { 0, 1, 0 }, // buttons
+};
+
+volatile static unsigned char current_adc, current_slow_adc;
+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;
-#define LAST_ADC (sizeof(adc_mux)/sizeof(adc_mux[0]))
-volatile static unsigned char current_adc;
-static unsigned char adc_ignore;
+
+static void setup_mux(unsigned char n)
+{
+ /* 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);
+ break;
+ case 1: // pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20
+ ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
+ break;
+ case 2: // pwmled 3: 1.1V, ADC4 (PA5), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX2);
+ break;
+ case AMBIENT_ADC: // ambient light: 1.1V, ADC5 (PA6), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX0);
+ break;
+ case BATTERY_ADC: // batt voltage: 1.1V, ADC6 (PA7), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX2) | _BV(MUX1);
+ break;
+ case ADC1_GAIN20: // gain stage offset: 1.1V, ADC1,1, gain 20
+ ADMUX = _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX0);
+ 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 ZERO_ADC: // zero: 1.1V, ADC1 (PA1), single-ended
+ ADMUX = _BV(REFS1) | _BV(MUX0);
+ break;
+ }
+}
static void start_next_adc()
{
- 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.
+ if (current_adc == 0) {
+ if (current_slow_adc > N_PWMLEDS) {
+ // read one of the non-PWMLED ADCs
+ current_adc = --current_slow_adc;
+ } else {
+ // no more non-PWMLEDs to do, start with PWMLEDs
+ current_adc = N_PWMLEDS-1;
+ }
+ } else if (current_adc >= N_PWMLEDS) {
+ // one of the non-PWMLED ADCs just finished, skip to PWMLEDs.
+ current_adc = N_PWMLEDS-1;
+ } else {
+ // next PWMLED
+ current_adc--;
}
- // 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
+#if 0
+ log_byte(0x90 + current_adc); // debug ADC switching
+#endif
+
+ 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
+ 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
+ if (zero_count > 1)
+ setup_mux(ZERO_ADC);
+ else
+ setup_mux(current_adc);
+
ADCSRA |= _BV(ADSC);
}
+void timer_start_slow_adcs()
+{
+ if (current_slow_adc > N_PWMLEDS) { // Don't start if in progress
+ log_byte(0x80 + current_slow_adc);
+ } else {
+ current_slow_adc = NUM_ADCS;
+ // TODO: kick the watchdog here
+ }
+}
+
+/*
+ * 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_slow_adc = NUM_ADCS;
+ current_adc = 0;
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;
+}
+
+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 0
- log_byte(0xF3);
- log_byte(current_adc);
- log_word(adcval);
-#endif
+ if (zero_count) {
+ if (zero_count > 1) {
+ ADCSRA |= _BV(ADSC);
+ zero_count--;
+ return;
+ } else {
+ setup_mux(current_adc);
+ zero_count = 0;
+ /* fall through */
+ }
+ }
+
+ if (drop_count) {
+ ADCSRA |= _BV(ADSC); // drop this one, start the next
+ drop_count--;
+ return;
+ }
- if (adc_ignore) {
+ if (read_count) {
ADCSRA |= _BV(ADSC);
- adc_ignore = 0;
+ adc_sum += adcval;
+ read_count--;
return;
}
- if (current_adc < N_PWMLEDS)
- pwmled_adc(current_adc, adcval);
- if (current_adc == AMBIENT_ADC)
- ambient_adc(adcval);
- // TODO battery sense, etc.
-
- start_next_adc();
-}
+ /*
+ * Now we have performed read_count measurements and have them
+ * in adc_sum.
+ */
-void timer_start_adcs()
-{
- if (current_adc == LAST_ADC) // Don't start if in progress
- start_next_adc();
+ // For inputs with gain, subtract the measured gain stage offset
+ if (current_adc < 2) {
+ uint16_t offset = adc1_gain20_offset
+ >> (ADC1_GAIN20_OFFSET_SHIFT - n_reads_log);
+
+ if (adc_sum > offset)
+ adc_sum -= offset;
+ else
+ adc_sum = 0;
+ }
+
+ switch (current_adc) {
+ case 0:
+ case 1:
+ case 2:
+ pwmled_adc(current_adc, adc_sum);
+ break;
+ case AMBIENT_ADC:
+ ambient_adc(adc_sum);
+ break;
+ case BATTERY_ADC:
+ battery_adc(adc_sum);
+ break;
+ case BUTTON_ADC:
+ button_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