Mercurial > templog

comparison main.c @ 60:2ebe33714989

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
average voltages
author Matt Johnston <matt@ucc.asn.au>
date Tue, 26 Jun 2012 00:00:42 +0800
parents d5b269352ba0
children 68c1e2b26bc5
comparison
equal deleted inserted replaced
59:d5b269352ba0 60:2ebe33714989
268 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) 268 ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
269 { 269 {
270 epoch_copy = clock_epoch; 270 epoch_copy = clock_epoch;
271 } 271 }
272 272
273 fprintf_P(crc_stdout, PSTR("START\n")); 273 fprintf_P(crc_stdout, PSTR("START\n"
274 fprintf_P(crc_stdout, PSTR("now=%lu\n" 274 "now=%lu\n"
275 "time_step=%hu\n" 275 "time_step=%hu\n"
276 "first_time=%lu\n" 276 "first_time=%lu\n"
277 "last_time=%lu\n" 277 "last_time=%lu\n"
278 "comms_time=%lu\n" 278 "comms_time=%lu\n"
279 "voltage=%hu\n" 279 "voltage=%hu\n"
280 "avrtemp=%hu\n"), 280 ),
281 epoch_copy, 281 epoch_copy,
282 (uint16_t)MEASURE_WAKE, 282 (uint16_t)MEASURE_WAKE,
283 first_measurement_clock, 283 first_measurement_clock,
284 last_measurement_clock, 284 last_measurement_clock,
285 last_comms_clock, 285 last_comms_clock,
626 PRR &= ~_BV(PRADC); 626 PRR &= ~_BV(PRADC);
627 627
628 // left adjust 628 // left adjust
629 ADMUX = _BV(ADLAR); 629 ADMUX = _BV(ADLAR);
630 630
631 // ADPS2 = /16 prescaler, 62khz at 1mhz clock 631 // /128 prescaler
632 ADCSRA = _BV(ADEN) | _BV(ADPS2); 632 ADCSRA = _BV(ADEN) | _BV(ADPS2);
633 633
634 // set to measure 1.1 reference 634 // set to measure 1.1 reference
635 ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1); 635 ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
636 _delay_ms(30); 636 // average a number of samples
637 // try a few times so it can stabilise 637 uint16_t sum = 0;
638 for (uint16_t n = 0; n < 20; n++) 638 uint8_t num = 0;
639 for (uint8_t n = 0; n < 20; n++)
639 { 640 {
640 ADCSRA |= _BV(ADSC); 641 ADCSRA |= _BV(ADSC);
641 loop_until_bit_is_clear(ADCSRA, ADSC); 642 loop_until_bit_is_clear(ADCSRA, ADSC);
642 } 643
643 uint8_t low_11 = ADCL; 644 uint8_t low_11 = ADCL;
644 uint8_t high_11 = ADCH; 645 uint8_t high_11 = ADCH;
645 uint16_t f_11 = low_11 + (high_11 << 8); 646 uint16_t val = low_11 + (high_11 << 8);
646 647
647 float res_volts = 1.1 * 1024 / f_11; 648 if (n >= 4)
648 649 {
650 sum += val;
651 num++;
652 }
653 }
654 ADCSRA = 0;
649 PRR |= _BV(PRADC); 655 PRR |= _BV(PRADC);
650 ADCSRA = 0; 656
657 float res_volts = 1.1 * 1024 * num / sum;
651 658
652 return 1000 * res_volts; 659 return 1000 * res_volts;
653 } 660 }
654
655 #if 0
656 // untested
657 static void
658 do_adc_335()
659 {
660 //PRR &= ~_BV(PRADC);
661
662 ADMUX = _BV(ADLAR);
663
664 // ADPS2 = /16 prescaler, 62khz at 1mhz clock
665 ADCSRA = _BV(ADEN) | _BV(ADPS2);
666
667 // measure value
668 ADCSRA |= _BV(ADSC);
669 loop_until_bit_is_clear(ADCSRA, ADSC);
670 uint8_t low = ADCL;
671 uint8_t high = ADCH;
672 uint16_t f_measure = low + (high << 8);
673
674 // set to measure 1.1 reference
675 ADMUX = _BV(ADLAR) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
676 ADCSRA |= _BV(ADSC);
677 loop_until_bit_is_clear(ADCSRA, ADSC);
678 uint8_t low_11 = ADCL;
679 uint8_t high_11 = ADCH;
680 uint16_t f_11 = low_11 + (high_11 << 8);
681
682 float res_volts = 1.1 * f_measure / f_11;
683
684 // 10mV/degree
685 // scale to 1/5 degree units above 0C
686 int temp = (res_volts - 2.73) * 500;
687 // XXX fixme
688 //measurements[n_measurements] = temp;
689 // XXX something if it hits the limit
690
691 // measure AVR internal temperature against 1.1 ref.
692 ADMUX = _BV(ADLAR) | _BV(MUX3) | _BV(REFS1) | _BV(REFS0);
693 ADCSRA |= _BV(ADSC);
694 loop_until_bit_is_clear(ADCSRA, ADSC);
695 uint16_t res_internal = ADCL;
696 res_internal |= ADCH << 8;
697
698 float internal_volts = res_internal * (1.1 / 1024.0);
699
700 // 1mV/degree
701 int internal_temp = (internal_volts - 2.73) * 5000;
702 // XXX fixme
703 //internal_measurements[n_measurements] = internal_temp;
704
705 printf_P("measure %d: external %d, internal %d, 1.1 %d\n",
706 n_measurements, temp, internal_temp, f_11);
707
708 n_measurements++;
709 //PRR |= _BV(PRADC);
710 }
711 #endif
712 661
713 static void 662 static void
714 do_measurement() 663 do_measurement()
715 { 664 {
716 uint8_t n_sensors; 665 uint8_t n_sensors;