diff options
Diffstat (limited to 'watch-library/watch/watch_utility.c')
-rw-r--r-- | watch-library/watch/watch_utility.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/watch-library/watch/watch_utility.c b/watch-library/watch/watch_utility.c index a0f361b4..bfa3073a 100644 --- a/watch-library/watch/watch_utility.c +++ b/watch-library/watch/watch_utility.c @@ -22,6 +22,7 @@ * SOFTWARE. */ +#include <math.h> #include "watch_utility.h" const char * watch_utility_get_weekday(watch_date_time date_time) { @@ -33,3 +34,23 @@ const char * watch_utility_get_weekday(watch_date_time date_time) { } return weekdays[(date_time.unit.day + 13 * (date_time.unit.month + 1) / 5 + date_time.unit.year + date_time.unit.year / 4 + 525) % 7]; } + +float watch_utility_thermistor_temperature(uint16_t value, bool highside, float b_coefficient, float nominal_temperature, float nominal_resistance, float series_resistance) { + float reading = (float)value; + + if (highside) { + reading = (1023.0 * series_resistance) / (reading / 64.0); + reading -= series_resistance; + } else { + reading = series_resistance / (65535.0 / value - 1.0); + } + + reading = reading / nominal_resistance; + reading = log(reading); + reading /= b_coefficient; + reading += 1.0 / (nominal_temperature + 273.15); + reading = 1.0 / reading; + reading -= 273.15; + + return reading; +} |