Diff: Sht31.cpp

Revision:

3:c4bd8cd5d566

Parent:

2:c84a60326ecf

diff -r c84a60326ecf -r c4bd8cd5d566 Sht31.cpp
--- a/Sht31.cpp	Mon Sep 11 13:51:03 2017 +0000
+++ b/Sht31.cpp	Wed Oct 03 13:51:56 2018 +0000
@@ -17,8 +17,8 @@
 #include "Sht31.h"
 #include "mbed.h"
 
-Sht31::Sht31(PinName sda, PinName scl) : _i2c(sda, scl) {
-    _i2caddr = (0x44 << 1);
+Sht31::Sht31(PinName sda, PinName scl, bool i2caddr) : _i2c(sda, scl) {
+    _i2caddr = !i2caddr ? (0x44 << 1) : (0x45 << 1);
     reset();
     readStatus();
 }
@@ -97,6 +97,50 @@
     return true;
 }
 
+
+bool Sht31::readTempHum(float &_temp, float &_humidity) {
+    char readbuffer[6];
+
+    writeCommand(SHT31_MEAS_HIGHREP);
+
+    wait_ms(500);
+    _i2c.read(_i2caddr, readbuffer, 6);
+    
+    uint16_t ST, SRH;
+    ST = readbuffer[0];
+    ST <<= 8;
+    ST |= readbuffer[1];
+
+    if (readbuffer[2] != crc8((uint8_t *) readbuffer, 2)) {
+        return false;
+    }
+
+    SRH = readbuffer[3];
+    SRH <<= 8;
+    SRH |= readbuffer[4];
+
+    if (readbuffer[5] != crc8((uint8_t *) readbuffer+3, 2)) {
+        return false;
+    }
+
+    double stemp = ST;
+    stemp *= 175;
+    stemp /= 0xffff;
+    stemp = -45 + stemp;
+    temp = stemp;
+    _temp = temp;
+
+    double shum = SRH;
+    shum *= 100;
+    shum /= 0xFFFF;
+
+    humidity = shum;
+    _humidity = humidity;
+
+    return true;
+}
+
+
 uint8_t Sht31::crc8(const uint8_t *data, int len) {
     const uint8_t POLYNOMIAL(0x31);
     uint8_t crc(0xFF);