X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?p=bike-lights.git;a=blobdiff_plain;f=firmware%2Fadc.c;h=6db036af530b124e8aec9db50e668b6802d669a9;hp=8ec62e2457e8419792f4ebd438c00a281c5f9ba4;hb=1f28156058ed3af9e87afdc60d631ca5a47eb2cb;hpb=3aa04c7f0ae362c4494d272ecf249d862e3aec01 diff --git a/firmware/adc.c b/firmware/adc.c index 8ec62e2..6db036a 100644 --- a/firmware/adc.c +++ b/firmware/adc.c @@ -3,56 +3,95 @@ #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 1: 1.1V, ADC0,1 (PA0,1), gain 20 - _BV(REFS1) | _BV(MUX3) | _BV(MUX1) | _BV(MUX0), - // 1: pwmled 2: 1.1V, ADC2,1 (PA2,1), gain 20 - _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1), - // 2: pwmled 3: 1.1V, ADC4 (PA5), single-ended - // _BV(REFS1) | _BV(MUX2), - // 2: for testing the same as 1 - _BV(REFS1) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1), - // 3: ambient light: 1.1V, ADC5 (PA6), single-ended - _BV(REFS1) | _BV(MUX2) | _BV(MUX0), - // 4: batt voltage: 1.1V, ADC6 (PA7), single-ended - _BV(REFS1) | _BV(MUX2) | _BV(MUX1), -}; - #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; - // TODO: kick the watchdog here. - return; -found: - 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 @@ -61,17 +100,25 @@ void init_adc() // ADCSRB |= _BV(GSEL); // gain 8 or 32 // Disable digital input on all bits used by ADC - DIDR0 = _BV(ADC0D) | _BV(ADC1D) | _BV(ADC2D) + DIDR0 = _BV(ADC0D) | _BV(ADC1D) | _BV(ADC2D) | _BV(ADC3D) | _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() @@ -83,31 +130,45 @@ void susp_adc() 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); + 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(); -} -