fix milesburton#151 - optimize setResolution

Author: RobTillaart

DallasTemperature.cpp

@@ -39,8 +39,12 @@ extern "C" {
 #define TEMP_11_BIT 0x5F // 11 bit
 #define TEMP_12_BIT 0x7F // 12 bit
 
+#define MAX_CONVERSION_TIMEOUT750
+
+// Alarm handler
 #define NO_ALARM_HANDLER ((AlarmHandler *)0)
 
+
 DallasTemperature::DallasTemperature() {
 #if REQUIRESALARMS
 setAlarmHandler(NO_ALARM_HANDLER);
@@ -112,7 +116,8 @@ void DallasTemperature::begin(void) {
 if (!parasite && readPowerSupply(deviceAddress))
 parasite = true;
 
-bitResolution = max(bitResolution, getResolution(deviceAddress));
+uint8_t b = getResolution(deviceAddress);
+if (b > bitResolution) bitResolution = b;
 }
 }
 }
@@ -254,69 +259,86 @@ void DallasTemperature::setResolution(uint8_t newResolution) {
 
 bitResolution = constrain(newResolution, 9, 12);
 DeviceAddress deviceAddress;
-for (int i = 0; i < devices; i++) {
+for (uint8_t i = 0; i < devices; i++) {
 getAddress(deviceAddress, i);
 setResolution(deviceAddress, bitResolution, true);
 }
-
 }
 
+/* PROPOSAL */
+
 // set resolution of a device to 9, 10, 11, or 12 bits
-// if new resolution is out of range, it is constrained.
+// if new resolution is out of range, 9 bits is used.
 bool DallasTemperature::setResolution(const uint8_t* deviceAddress,
-uint8_t newResolution, bool skipGlobalBitResolutionCalculation) {
-
-// ensure same behavior as setResolution(uint8_t newResolution)
-newResolution = constrain(newResolution, 9, 12);
+ uint8_t newResolution, bool skipGlobalBitResolutionCalculation) {
 
-// return when stored value == new value
-if (getResolution(deviceAddress) == newResolution)
-return true;
-
-ScratchPad scratchPad;
-if (isConnected(deviceAddress, scratchPad)) {
+ bool success = false;
 
-// DS1820 and DS18S20 have no resolution configuration register
-if (deviceAddress[0] != DS18S20MODEL) {
-
-switch (newResolution) {
-case 12:
-scratchPad[CONFIGURATION] = TEMP_12_BIT;
-break;
-case 11:
-scratchPad[CONFIGURATION] = TEMP_11_BIT;
-break;
-case 10:
-scratchPad[CONFIGURATION] = TEMP_10_BIT;
-break;
-case 9:
-default:
-scratchPad[CONFIGURATION] = TEMP_9_BIT;
-break;
-}
-writeScratchPad(deviceAddress, scratchPad);
-
-// without calculation we can always set it to max
-bitResolution = max(bitResolution, newResolution);
-
-if (!skipGlobalBitResolutionCalculation
-&& (bitResolution > newResolution)) {
-bitResolution = newResolution;
-DeviceAddress deviceAddr;
-for (int i = 0; i < devices; i++) {
-getAddress(deviceAddr, i);
-bitResolution = max(bitResolution,
-getResolution(deviceAddr));
-}
-}
-}
-return true; // new value set
-}
+ // DS1820 and DS18S20 have no resolution configuration register
+ if (deviceAddress[0] == DS18S20MODEL)
+ {
+ success = true;
+ }
+ else
+ {
+
+ // handle the sensors with configuration register
+ newResolution = constrain(newResolution, 9, 12);
+
+ uint8_t newValue = 0;
+ ScratchPad scratchPad;
+
+ // we can only update the sensor if it is connected
+ if (isConnected(deviceAddress, scratchPad))
+ {
+ switch (newResolution) {
+ case 12:
+ newValue = TEMP_12_BIT;
+ break;
+ case 11:
+ newValue = TEMP_11_BIT;
+ break;
+ case 10:
+ newValue = TEMP_10_BIT;
+ break;
+ case 9:
+ default:
+ newValue = TEMP_9_BIT;
+ break;
+ }
+
+ // if it needs to be updated we write the new value
+ if (scratchPad[CONFIGURATION] != newValue)
+ {
+scratchPad[CONFIGURATION] = newValue;
+ writeScratchPad(deviceAddress, scratchPad);
+ }
+ // done
+ success = true;
+ }
+ }
 
-return false;
+ // do we need to update the max resolution used?
+ if (skipGlobalBitResolutionCalculation == false)
+ {
+ bitResolution = newResolution;
+ if (devices > 1)
+ {
+ for (uint8_t i = 0; i < devices; i++)
+ {
+ if (bitResolution == 12) break;
+ DeviceAddress deviceAddr;
+ getAddress(deviceAddr, i);
+ uint8_t b = getResolution(deviceAddr);
+ if (b > bitResolution) bitResolution = b;
+ }
+ }
+ }
 
+ return success;
 }
 
+
 // returns the global resolution
 uint8_t DallasTemperature::getResolution() {
 return bitResolution;
@@ -350,6 +372,7 @@ uint8_t DallasTemperature::getResolution(const uint8_t* deviceAddress) {
 
 }
 
+
 // sets the value of the waitForConversion flag
 // TRUE : function requestTemperature() etc returns when conversion is ready
 // FALSE: function requestTemperature() etc returns immediately (USE WITH CARE!!)
@@ -475,12 +498,11 @@ bool DallasTemperature::requestTemperaturesByIndex(uint8_t deviceIndex) {
 // Fetch temperature for device index
 float DallasTemperature::getTempCByIndex(uint8_t deviceIndex) {
 
-DeviceAddress deviceAddress;
+DeviceAddress deviceAddress;
 if (!getAddress(deviceAddress, deviceIndex)) {
 return DEVICE_DISCONNECTED_C;
 }
 return getTempC((uint8_t*) deviceAddress);
-
 }
 
 // Fetch temperature for device index

DallasTemperature.h

@@ -37,9 +37,6 @@
 #define DEVICE_DISCONNECTED_F -196.6
 #define DEVICE_DISCONNECTED_RAW -7040
 
-// Other
-#define MAX_CONVERSION_TIMEOUT 750
-
 // For readPowerSupply on oneWire bus
 #ifndef nullptr
 #define nullptr NULL