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Use More Generous Conversion Times on DS18B20

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This commit is contained in:
seiichiro 2021-03-28 19:06:22 +02:00
parent 5809f514f0
commit b498364a57
1 changed files with 22 additions and 7 deletions
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29
lib/DS18B20/DS18B20.cpp
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@ -33,19 +33,19 @@ DS18B20::DS18B20(uint8_t owpin, uint8_t resbits = 12, bool para = false) {
switch(resbits) { switch(resbits) {
case 9 : case 9 :
resolution = DS18B20_9_BIT; resolution = DS18B20_9_BIT;
convtime = 100; convtime = 300;
break; break;
case 10 : case 10 :
resolution = DS18B20_10_BIT; resolution = DS18B20_10_BIT;
convtime = 200; convtime = 600;
break; break;
case 11 : case 11 :
resolution = DS18B20_11_BIT; resolution = DS18B20_11_BIT;
convtime = 400; convtime = 900;
break; break;
default : default :
resolution = DS18B20_12_BIT; resolution = DS18B20_12_BIT;
convtime = 800; convtime = 1200;
} }
} }
@ -53,14 +53,14 @@ void DS18B20::initialize(void){
onewire->reset(); onewire->reset();
onewire->reset_search(); onewire->reset_search();
sensorcount = 0; sensorcount = 0;
delay(250);
while (onewire->search(addr)) { while (onewire->search(addr)) {
if (OneWire::crc8( addr, 7) == addr[7] && addr[0] != 0x00) { if (OneWire::crc8( addr, 7) == addr[7] && addr[0] != 0x00) {
sensorcount++; sensorcount++;
setResolution(); setResolution();
} }
} }
delay(500);
} }
uint8_t DS18B20::numBytes(void){ uint8_t DS18B20::numBytes(void){
@ -107,7 +107,20 @@ uint8_t DS18B20::getSensorData(char *payload, uint8_t startbyte){
if (OneWire::crc8(data, 8) == data[8]) { if (OneWire::crc8(data, 8) == data[8]) {
int16_t rawTemp = (((int16_t)data[1]) << 8) | data[0]; int16_t rawTemp = (((int16_t)data[1]) << 8) | data[0];
value = ((float)0.0625*rawTemp)*100; byte cfg = (data[4] & 0x60);
// at lower res, the low bits are undefined, so let's zero them
switch (cfg) {
case 0x00 :
rawTemp = rawTemp & ~7;
break;
case 0x20 :
rawTemp = rawTemp & ~3;
break;
case 0x40 :
rawTemp = rawTemp & ~1;
break;
}
value = ((float)rawTemp/16.0)*100;
} else { } else {
value = -85; value = -85;
} }
@ -116,7 +129,9 @@ uint8_t DS18B20::getSensorData(char *payload, uint8_t startbyte){
payload[startbyte+1] = (value >> 8) & 0XFF; payload[startbyte+1] = (value >> 8) & 0XFF;
// Set next Startbyte // Set next Startbyte
startbyte += 2; startbyte += 2;
delay(50);
} }
} }
onewire->depower();
return startbyte; return startbyte;
} }