add code for SHT4X, ENV4

lib/iictask/SHT4X.cpp

@@ -0,0 +1,128 @@
+#include "SHT4X.h"
+uint8_t crc8(const uint8_t *data, int len) {
+    /*
+     *
+     * CRC-8 formula from page 14 of SHT spec pdf
+     *
+     * Test data 0xBE, 0xEF should yield 0x92
+     *
+     * Initialization data 0xFF
+     * Polynomial 0x31 (x8 + x5 +x4 +1)
+     * Final XOR 0x00
+     */
+
+    const uint8_t POLYNOMIAL(0x31);
+    uint8_t crc(0xFF);
+
+    for (int j = len; j; --j) {
+        crc ^= *data++;
+
+        for (int i = 8; i; --i) {
+            crc = (crc & 0x80) ? (crc << 1) ^ POLYNOMIAL : (crc << 1);
+        }
+    }
+    return crc;
+}
+
+bool SHT4X::begin(TwoWire* wire, uint8_t addr) {
+    _addr = addr;
+    _wire = wire;
+    int error;
+    _wire->beginTransmission(addr);
+    error = _wire->endTransmission();
+    if (error == 0) {
+        return true;
+    }
+    return false;
+}
+
+bool SHT4X::update() {
+    uint8_t readbuffer[6];
+    uint8_t cmd       = SHT4x_NOHEAT_HIGHPRECISION;
+    uint16_t duration = 10;
+
+    if (_heater == SHT4X_NO_HEATER) {
+        if (_precision == SHT4X_HIGH_PRECISION) {
+            cmd      = SHT4x_NOHEAT_HIGHPRECISION;
+            duration = 10;
+        }
+        if (_precision == SHT4X_MED_PRECISION) {
+            cmd      = SHT4x_NOHEAT_MEDPRECISION;
+            duration = 5;
+        }
+        if (_precision == SHT4X_LOW_PRECISION) {
+            cmd      = SHT4x_NOHEAT_LOWPRECISION;
+            duration = 2;
+        }
+    }
+
+    if (_heater == SHT4X_HIGH_HEATER_1S) {
+        cmd      = SHT4x_HIGHHEAT_1S;
+        duration = 1100;
+    }
+    if (_heater == SHT4X_HIGH_HEATER_100MS) {
+        cmd      = SHT4x_HIGHHEAT_100MS;
+        duration = 110;
+    }
+
+    if (_heater == SHT4X_MED_HEATER_1S) {
+        cmd      = SHT4x_MEDHEAT_1S;
+        duration = 1100;
+    }
+    if (_heater == SHT4X_MED_HEATER_100MS) {
+        cmd      = SHT4x_MEDHEAT_100MS;
+        duration = 110;
+    }
+
+    if (_heater == SHT4X_LOW_HEATER_1S) {
+        cmd      = SHT4x_LOWHEAT_1S;
+        duration = 1100;
+    }
+    if (_heater == SHT4X_LOW_HEATER_100MS) {
+        cmd      = SHT4x_LOWHEAT_100MS;
+        duration = 110;
+    }
+    // _i2c.writeByte(_addr, cmd, 1);
+    _wire->beginTransmission(_addr);
+    _wire->write(cmd);
+    _wire->write(1);
+    _wire->endTransmission();
+
+
+    delay(duration);
+
+    _wire->requestFrom(_addr, (uint8_t)6);
+
+    for (uint16_t i = 0; i < 6; i++) {
+        readbuffer[i] = _wire->read();
+    }
+
+    if (readbuffer[2] != crc8(readbuffer, 2) ||
+        readbuffer[5] != crc8(readbuffer + 3, 2)) {
+        return false;
+    }
+
+    float t_ticks  = (uint16_t)readbuffer[0] * 256 + (uint16_t)readbuffer[1];
+    float rh_ticks = (uint16_t)readbuffer[3] * 256 + (uint16_t)readbuffer[4];
+
+    cTemp    = -45 + 175 * t_ticks / 65535;
+    humidity = -6 + 125 * rh_ticks / 65535;
+    humidity = min(max(humidity, (float)0.0), (float)100.0);
+    return true;
+}
+
+void SHT4X::setPrecision(sht4x_precision_t prec) {
+    _precision = prec;
+}
+
+sht4x_precision_t SHT4X::getPrecision(void) {
+    return _precision;
+}
+
+void SHT4X::setHeater(sht4x_heater_t heat) {
+    _heater = heat;
+}
+
+sht4x_heater_t SHT4X::getHeater(void) {
+    return _heater;
+}