From: Keith Packard Date: Thu, 23 May 2013 01:31:15 +0000 (-0600) Subject: altos: MS5607 pressure computation for low temperatures was wrong X-Git-Tag: 1.2.9.4~133^2 X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=b363a628fc6137c3395a48ef13de7a799ec3e2c3 altos: MS5607 pressure computation for low temperatures was wrong Second correction only applies to temps < -15°C, not 15°C. Signed-off-by: Keith Packard --- diff --git a/src/drivers/ao_ms5607_convert.c b/src/drivers/ao_ms5607_convert.c index e61d19ed..bfb952a4 100644 --- a/src/drivers/ao_ms5607_convert.c +++ b/src/drivers/ao_ms5607_convert.c @@ -42,11 +42,14 @@ ao_ms5607_convert(struct ao_ms5607_sample *sample, struct ao_ms5607_value *value int32_t TEMPM = TEMP - 2000; int64_t OFF2 = (61 * (int64_t) TEMPM * (int64_t) TEMPM) >> 4; int64_t SENS2 = 2 * (int64_t) TEMPM * (int64_t) TEMPM; - if (TEMP < 1500) { + if (TEMP < -1500) { int32_t TEMPP = TEMP + 1500; - int64_t TEMPP2 = TEMPP * TEMPP; - OFF2 = OFF2 + 15 * TEMPP2; - SENS2 = SENS2 + 8 * TEMPP2; + /* You'd think this would need a 64-bit int, but + * that would imply a temperature below -327.67Â°C... + */ + int32_t TEMPP2 = TEMPP * TEMPP; + OFF2 = OFF2 + (int64_t) 15 * TEMPP2; + SENS2 = SENS2 + (int64_t) 8 * TEMPP2; } TEMP -= T2; OFF -= OFF2;