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Merge pull request #3955 from zuckschwerdt/feat-w1parasite 

Add W1_PARASITE_POWER optimization for DS18X20
This commit is contained in:
Theo Arends 2018-10-01 21:31:36 +02:00 committed by GitHub
parent 2f429e5a44 3280c7d177
commit c0117e5315
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 27 additions and 1 deletions
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1
sonoff/user_config.h
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@ -271,6 +271,7 @@
// -- One wire sensors ----------------------------
// WARNING: Select none for default one DS18B20 sensor or enable one of the following two options for multiple sensors
#define USE_DS18x20 // Optional for more than one DS18x20 sensors with id sort, single scan and read retry (+1k3 code)
//#define W1_PARASITE_POWER // If using USE_DS18x20 then optimize for parasite powered sensors
//#define USE_DS18x20_LEGACY // Optional for more than one DS18x20 sensors with dynamic scan using library OneWire (+1k5 code)
// -- I2C sensors ---------------------------------

27
sonoff/xsns_05_ds18x20.ino
View File

@ -49,6 +49,10 @@ struct DS18X20STRUCT {
uint8_t ds18x20_sensors = 0;
uint8_t ds18x20_pin = 0;
char ds18x20_types[12];
#ifdef W1_PARASITE_POWER
uint8_t ds18x20_sensor_curr = 0;
unsigned long w1_power_until = 0;
#endif
/*********************************************************************************************\
* Embedded tuned OneWire library
@ -285,7 +289,14 @@ void Ds18x20Init()
void Ds18x20Convert()
{
OneWireReset();
#ifdef W1_PARASITE_POWER
// With parasite power address one sensor at a time
if (++ds18x20_sensor_curr >= ds18x20_sensors)
ds18x20_sensor_curr = 0;
OneWireSelect(ds18x20_sensor[ds18x20_sensor_curr].address);
#else
OneWireWrite(W1_SKIP_ROM); // Address all Sensors on Bus
#endif
OneWireWrite(W1_CONVERT_TEMP); // start conversion, no parasite power on at the end
// delay(750); // 750ms should be enough for 12bit conv
}
@ -334,6 +345,9 @@ bool Ds18x20Read(uint8_t sensor)
OneWireWrite(data[4]); // Configuration Register
OneWireSelect(ds18x20_sensor[index].address);
OneWireWrite(W1_WRITE_EEPROM); // Save scratchpad to EEPROM
#ifdef W1_PARASITE_POWER
w1_power_until = millis() + 10; // 10ms specified duration for EEPROM write
#endif
}
temp12 = (data[1] << 8) + data[0];
if (temp12 > 2047) {
@ -374,7 +388,18 @@ void Ds18x20Name(uint8_t sensor)
void Ds18x20EverySecond()
{
if (uptime &1) {
#ifdef W1_PARASITE_POWER
// skip access if there is still an eeprom write ongoing
unsigned long now = millis();
if (now < w1_power_until)
return;
#endif
if (uptime & 1
#ifdef W1_PARASITE_POWER
// if more than 1 sensor and only parasite power: convert every cycle
|| ds18x20_sensors >= 2
#endif
) {
// 2mS
Ds18x20Convert(); // Start conversion, takes up to one second
} else {