diff options
Diffstat (limited to 'src/ao_convert.c')
| -rw-r--r-- | src/ao_convert.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/ao_convert.c b/src/ao_convert.c index 57ed7370..f29ce9e9 100644 --- a/src/ao_convert.c +++ b/src/ao_convert.c @@ -49,7 +49,15 @@ ao_temp_to_dC(int16_t temp) __reentrant int16_t ret; ao_mutex_get(&ao_temp_mutex); - ret = (int16_t) ((temp >> 4) * 3300L / 2047L) - 500; + /* Output voltage at 0°C = 0.755V + * Coefficient = 0.00247V/°C + * Reference voltage = 1.25V + * + * temp = ((value / 32767) * 1.25 - 0.755) / 0.00247 + * = (value - 19791.268) / 32768 * 1.25 / 0.00247 + * ≃ (value - 19791) * 1012 / 65536 + */ + ret = ((temp - 19791) * 1012L) >> 16; ao_mutex_put(&ao_temp_mutex); return ret; } |