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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,132 @@ | ||
| /* ZACwire - Library for reading temperature sensors TSIC 206/306/506 | ||
| created by Adrian Immer in 2020 | ||
| v2.0.0 | ||
| */ | ||
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| #include "ZACwire.h" | ||
| #include "Arduino.h" | ||
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| #if !defined(ESP32) && !defined(ESP8266) //initialize static variables for AVR boards | ||
| uint8_t ZACwire::bitThreshold; | ||
| uint16_t ZACwire::measuredTimeDiff; | ||
| volatile uint8_t ZACwire::bitCounter; | ||
| volatile bool ZACwire::backUP; | ||
| volatile uint16_t ZACwire::rawData[2]; | ||
| volatile uint8_t ZACwire::heartbeat; | ||
| #endif | ||
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| ZACwire::ZACwire(uint8_t pin, int16_t sensor) : _pin{pin}, _sensor{sensor} { | ||
| bitCounter = 0; | ||
| bitThreshold = 0; | ||
| } | ||
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| bool ZACwire::begin() { //start collecting data, needs to be called over 2ms before first getTemp() | ||
| pinMode(_pin, INPUT_PULLUP); | ||
| for (uint8_t i=20; pulseIn(_pin,LOW,500);) { //wait for time without transmission | ||
| if (!--i) return false; | ||
| yield(); | ||
| } | ||
| uint8_t strobeTime = pulseIn(_pin, LOW); //check for signal and measure strobeTime | ||
| if (!strobeTime) return false; //abort if there is no incoming signal | ||
| measuredTimeDiff = micros(); //set timestamp of first rising edge for ISR | ||
| bitThreshold = strobeTime * 2.5; | ||
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| uint8_t isrPin = digitalPinToInterrupt(_pin); | ||
| if (isrPin == 255) return false; | ||
| #if defined(ESP32) || defined(ESP8266) | ||
| attachInterruptArg(isrPin, isrHandler, this, RISING); | ||
| #else | ||
| attachInterrupt(isrPin, read, RISING); | ||
| #endif | ||
| return true; | ||
| } | ||
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| float ZACwire::getTemp(uint8_t maxChangeRate, bool useBackup) { //return temperature in °C | ||
| if (connectionCheck()) adjustBitThreshold(); | ||
| else return errorNotConnected; | ||
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| if (bitCounter != Bit::finished) useBackup = true; //when newer reading is incomplete | ||
| uint16_t temp{rawData[backUP^useBackup]}; //get rawData from ISR | ||
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| if (tempCheck(temp)) { | ||
| temp >>= 1; //delete second parity bit | ||
| temp = (temp >> 2 & 1792) | (temp & 255); //delete first " " | ||
| if (!prevTemp) prevTemp = temp; | ||
| int16_t grad = (temp - prevTemp) / (heartbeat|1);//grad is [°C/s] | ||
| if (abs(grad) < maxChangeRate) { //limit change rate to detect misreadings | ||
| prevTemp = temp; | ||
| heartbeat = 0; | ||
| if (_sensor < 400) return ((temp * 250L >> 8) - 499) / 10.0; //use different formula for 206&306 or 506 | ||
| else return ((temp * 175L >> 9) - 99) / 10.0; | ||
| } | ||
| } | ||
| return useBackup ? errorMisreading : getTemp(maxChangeRate,!useBackup); //restart with backUP rawData or return error value 222 | ||
| } | ||
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| void ZACwire::end() { | ||
| detachInterrupt(digitalPinToInterrupt(_pin)); | ||
| } | ||
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| void ZACwire::isrHandler(void* ptr) { | ||
| static_cast<ZACwire*>(ptr)->read(); | ||
| } | ||
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| void ZACwire::read() { //get called with every rising edge | ||
| if (++bitCounter < Bit::lastZero) return; //first 4 bits always =0 | ||
| uint16_t microtime = micros(); | ||
| measuredTimeDiff = microtime - measuredTimeDiff; //measure time to previous rising edge | ||
| if (measuredTimeDiff >> 10) { //first start bit, so big time difference | ||
| if (bitCounter == 20) { | ||
| backUP = !backUP; //save backup, if it successfully counted 20 bits | ||
| ++heartbeat; //give a sign of life to getTemp() | ||
| } | ||
| bitCounter = 0; | ||
| } | ||
| else if (bitCounter == Bit::lastZero) { | ||
| rawData[backUP] = measuredTimeDiff<<1 | 2; //send measuredTimeDiff for calculating bitThreshold and add prefix "10" to temp | ||
| } | ||
| else { | ||
| if (bitCounter == Bit::afterStop) microtime += bitThreshold>>2; //convert timestamp at stop bit to normal 0 bit | ||
| if (~rawData[backUP] & 1) measuredTimeDiff += bitThreshold>>1; //add 1/2 bitThreshold if previous bit was 0 (for normalisation) | ||
| rawData[backUP] <<= 1; | ||
| if (measuredTimeDiff < bitThreshold) rawData[backUP] |= 1; | ||
| } | ||
| measuredTimeDiff = microtime; | ||
| } | ||
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| bool ZACwire::connectionCheck() { | ||
| if (heartbeat) timeLastHB = 0; | ||
| else if (!bitThreshold) { //use bitThreshold to check if begin() was already called | ||
| if (begin()) delay(3); | ||
| else return false; | ||
| } | ||
| else if (!timeLastHB) timeLastHB = millis(); //record first missing heartbeat | ||
| else if (millis() - timeLastHB > timeout) return false; | ||
| return true; | ||
| } | ||
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| void ZACwire::adjustBitThreshold() { | ||
| if (bitCounter < Bit::lastZero || bitCounter > Bit::afterStop) return; //adjust bitThreshold only before rawData is used for temperature | ||
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| uint16_t newBitThreshold = (rawData[backUP] >> (bitCounter - 4));//separate newBitThreshold from temperature bits | ||
| newBitThreshold *= 1.25 / 5.25; | ||
| bitThreshold < newBitThreshold ? ++bitThreshold : --bitThreshold; | ||
| } | ||
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| bool ZACwire::tempCheck(uint16_t rawTemp) { | ||
| if (rawTemp >> 14 != 2 || rawTemp & 512) return false; //check for prefix "10" and stop bit=0 | ||
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| bool parity{true}; | ||
| for (uint8_t i{0}; i<9; ++i) parity ^= rawTemp & 1 << i; | ||
| if (parity) for (uint8_t i{10}; i<14; ++i) parity ^= rawTemp & 1 << i; | ||
| return parity; | ||
| } |
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