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Divisions turned into multiplications

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As correctly stated by Mausy5043, the division is quite slow in most
microcontrollers, so I have replaced them with multiplications.
This commit is contained in:
J.M. Dana 2015-10-06 23:42:19 +01:00
parent 5fb1668822
commit 5bc0a5c796
1 changed files with 6 additions and 6 deletions
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12
DHT.cpp
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@ -46,7 +46,7 @@ float DHT::readTemperature(bool S, bool force) {
f = data[2] & 0x7F; f = data[2] & 0x7F;
f *= 256; f *= 256;
f += data[3]; f += data[3];
f /= 10; f *= 0.1;
if (data[2] & 0x80) { if (data[2] & 0x80) {
f *= -1; f *= -1;
} }
@ -60,11 +60,11 @@ float DHT::readTemperature(bool S, bool force) {
} }
float DHT::convertCtoF(float c) { float DHT::convertCtoF(float c) {
return c * 9 / 5 + 32; return c * 1.8 + 32;
} }
float DHT::convertFtoC(float f) { float DHT::convertFtoC(float f) {
return (f - 32) * 5 / 9; return (f - 32) * 0.55555;
} }
float DHT::readHumidity(bool force) { float DHT::readHumidity(bool force) {
@ -79,7 +79,7 @@ float DHT::readHumidity(bool force) {
f = data[0]; f = data[0];
f *= 256; f *= 256;
f += data[1]; f += data[1];
f /= 10; f *= 0.1;
break; break;
} }
} }
@ -194,11 +194,11 @@ boolean DHT::read(bool force) {
_lastresult = false; _lastresult = false;
return _lastresult; return _lastresult;
} }
data[i/8] <<= 1; data[i * 0.125] <<= 1;
// Now compare the low and high cycle times to see if the bit is a 0 or 1. // Now compare the low and high cycle times to see if the bit is a 0 or 1.
if (highCycles > lowCycles) { if (highCycles > lowCycles) {
// High cycles are greater than 50us low cycle count, must be a 1. // High cycles are greater than 50us low cycle count, must be a 1.
data[i/8] |= 1; data[i * 0.125] |= 1;
} }
// Else high cycles are less than (or equal to, a weird case) the 50us low // Else high cycles are less than (or equal to, a weird case) the 50us low
// cycle count so this must be a zero. Nothing needs to be changed in the // cycle count so this must be a zero. Nothing needs to be changed in the